MUSCULAR SYSTEM. Jhia Anjela D. Rivera Department of Biological Sciences, School of Science and Technology, Centro Escolar University

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1 MUSCULAR SYSTEM Jhia Anjela D. Rivera Department of Biological Sciences, School of Science and Technology, Centro Escolar University

2 OUTLINE Overview Major types of muscles Muscle nomenclature Attachments of skeletal muscles Muscle forms Regional study of skeletal muscles Muscles of the thorax Muscles of respiration Muscles of the back Muscles of the anterior abdomen Muscles of the posterior abdomen Muscles of the perineum Muscles of the upper extremity Muscles of the lower extremity Identify origin, insertion, action and nerve supply Clinical considerations

3 OBJECTIVES To describe the properties and functions of the different muscle tissues. To identify the contrast between skeletal, cardiac and smooth muscles. To know the different bases for naming muscles. To differentiate muscular attachments.

4 MUSCULAR SYSTEM Generally regarded as consisting of one type of muscle found in the body skeletal muscle

5 FUNCTIONS OF THE MUSCULAR SYSTEM Muscle tissue is highly specialized to contract, or shorten, forcefully. The process of metabolism extracts energy from nutrient molecules. Part of that energy is used for muscle contraction, and the remainder is used for other cell processes or is released as heat. Body movement Maintenance of posture Respiration Production of body heat Communication Constriction of organs and vessels Heart beat

6 PROPERTIES OF MUSCLES Muscle has four major functional properties: Contractility is the ability of muscle to shorten forcefully Excitability is the capacity of muscle to respond to a stimulus Extensibility means that muscle can be stretched beyond its normal resting length and is still able to contract Elasticity is the ability of muscle to recoil to its original resting length after it has been stretched

TYPES OF MUSCLE TISSUES Forms the majority of the muscle tissue in the body Consists of parallel bundles of long, multinucleated fibers with transverse

gives form to the body Striated muscle found only in the walls of the heart (myocardium) and in some of the large vessels close to where they join the heart

visceral motor nerves Absence of stripes Consists of elongated or spindle shaped fibers capable of slow and sustained contractions Found in the walls of

7 TYPES OF MUSCLE TISSUES Forms the majority of the muscle tissue in the body Consists of parallel bundles of long, multinucleated fibers with transverse stripes Capable of powerful contractions, innervated by somatic and branchial motor nerves Used to move bones and other structures, provides support and gives form to the body Striated muscle found only in the walls of the heart (myocardium) and in some of the large vessels close to where they join the heart Consists of a branching network of individual cells linked electrically and mechanically Less powerful contractions, resistant to fatigue Innervated by visceral motor nerves Absence of stripes Consists of elongated or spindle shaped fibers capable of slow and sustained contractions Found in the walls of blood vessels (tunica media), associated with hair follicles in the skin, in the eyeballs, GIT, urinary system Innervated by visceral motor nerves Skeletal Cardiac Smooth

8 MUSCLE NOMENCLATURE Muscles are named according to: Location Size Shape Orientation of fasciculi Origin and insertion Number of heads Function

9 LOCATION A pectoralis (chest) muscle is located in the chest, a gluteus (buttock) muscle is located in the buttock, and a brachial (arm) muscle is located in the arm.

10 SIZE The gluteus maximus (large) is the largest muscle of the buttock, and the gluteus minimus (small) is the smallest. A longus (long) muscle is longer than a brevis (short) muscle.

11 SHAPE The deltoid (triangular) muscle is triangular, a quadratus (quadrate) muscle is rectangular, and a teres (round) muscle is round.

12 ORIENTATION OF FASCICULI. A rectus (straight) muscle has muscle fasciculi running straight with the axis of the structure to which the muscle is associated, whereas the fasciculi of an oblique muscle lie oblique to the longitudinal axis of the structure.

13 ORIGIN AND INSERTION The sternocleidomastoid originates on the sternum and clavicle and inserts onto the mastoid process of the temporal bone. The brachioradialis originates in the arm (brachium) and inserts onto the radius.

14 NUMBER OF HEADS A biceps muscle has two heads, and a triceps muscle has three heads.

15 FUNCTION An abductor moves a structure away from the midline, and an adductor moves a structure toward the midline. The masseter (a chewer) is a chewing muscle

16 ATTACHMENTS OF SKELETAL MUSCLES Tendon muscle to bone Aponeuroses muscle to muscle Origin (head) stationary end of the muscle Insertion end of the muscle attached to the bone Belly part of the muscle between the origin and insertion

17 REGIONAL STUDY OF SKELETAL MUSCLES Thorax Respiration Back Anterior abdomen Posterior abdomen Perineum Upper extremity Lower extremity

18 MUSCLE OF THE THORAX AND RESPIRATION MUSCLE ORIGIN INSERTION INNERVATION ACTION External intercostal (11 muscles) Internal intercostal (11 muscles) Lower border of a rib Upper border of the rib below Within intercostal space, each extends from the tubercle of the rib dorsally to the cartilage of the rib ventrally Ridge on the inner surface near lower border of the rib Upper border of the rib below Within intercostal space, each extends from the sternum ventrally to the angle of the rib dorsally Intercostal nerves Intercostal nerves Elevate the ribs; active during normal inspiration Elevate the ribs; active during inspiration and expiration

19 MUSCLE OF THE THORAX AND RESPIRATION MUSCLE ORIGIN INSERTION INNERVATION ACTION Transversus thoracis Subclavius Inner surface of body; xiphoid process, posterior surface of the sternum 1 st rib and its cartilage at their junction Costal cartilages of ribs 2-6, inner surfaces of costal cartilages 2-6 Groove on the lower surface of the middle 1/3 rd of clavicle Subcostalis angle of ribs angle of a rib 2-3 ribs above origin Diaphragm xiphoid process, costal margin, fascia over the quadratus lumborum and psoas major mm.(lateral & medial arcuate ligaments), vertebral bodies L1-L3 central tendon of the diaphragm Intercostal nerves Nerve to subclavius from upper trunk of brachial plexus Intercostal nerves phrenic nerve (C3-C5) compresses the thorax for forced expiration Depresses and pulls clavicle forward compresses the intercostal spaces pushes the abdominal viscera inferiorly, increasing the volume of the thoracic cavity (inspiration)

20 MUSCLES OF THE THORAX AND RESPIRATION

21 MUSCLE OF THE BACK MUSCLE ORIGIN INSERTION INNERVATION ACTION Erector spinae iliac crest, sacrum, transverse and spinous processes of vertebrae and supraspinal ligament Iliocostalis iliac crest and sacrum Interspinales Intertransversarii upper border of spinous process upper border of transverse process angles of the ribs, transverse and spinous processes of vertebrae, posterior aspect of the skull angles of the ribs lower border of spinous process above lower border of transverse process above segmentally innervated by dorsal primary rami of spinal nerves C1-S5 dorsal primary rami of spinal nerves C4-S5 dorsal primary rami of spinal nerves C1-L5 dorsal primary rami of spinal nerves C1-L5 extends and laterally bends the trunk, neck and head extends and laterally bends the trunk and neck extend trunk and neck laterally bend trunk and neck

22 MUSCLE OF THE BACK MUSCLE ORIGIN INSERTION INNERVATION ACTION Longissimus transverse process at inferior vertebral levels Multifidus sacrum, transverse processes of C3-L5 Obliquus capitis inferior Obliquus capitis superior spinous process of the axis transverse process of atlas transverse process at superior vertebral levels and mastoid process spinous processes 2-4 vertebral levels superior to their origin transverse process of atlas occipital bone above inferior nuchal line dorsal primary rami of spinal nerves C1-S1 dorsal primary rami of spinal nerves C1-L5 suboccipital nerve (DPR of C1) suboccipital nerve (DPR of C1) extends and laterally bends the trunk, neck and head extend and laterally bend trunk and neck, rotate to opposite side rotates the head to the same side extends the head, rotates the head to the same side

23 MUSCLE OF THE BACK MUSCLE ORIGIN INSERTION INNERVATION ACTION Rectus capitis posterior major Rectus capitis posterior minor spinous process of axis posterior tubercle of atlas inferior nuchal line inferior nuchal line medially Rotatores transverse processes long rotatores: spines 2 vertebrae above origin; short rotatores: spines 1 vertebrae above origin Semispinalis transverse processes of C7-T12 capitis: back of skull between nuchal lines; cervicis & thoracis: spines 4-6 vertebrae above origin suboccipital nerve (DPR of C1) suboccipital nerve (DPR of C1) dorsal primary rami of spinal nerves C1-L5 dorsal primary rami of spinal nerves C1-T12 extends the head, rotate to same side extends the head rotates the vertebral column to the opposite side extends the trunk and laterally bends the trunk, rotates the trunk to the opposite side

24 MUSCLE OF THE BACK MUSCLE ORIGIN INSERTION INNERVATION ACTION Spinalis spinous processes at inferior vertebral levels spinous processes at superior vertebral levels and base of the skull dorsal primary rami of spinal nerves C2-L3 extends and laterally bends trunk and neck Splenius ligamentum nuchae and spines C7-T6 capitis: mastoid process & superior nuchal line laterally; cervicis: posterior tubercles of C1-C3 vertebrae dorsal primary rami of spinal nerves C2-C6 extends and laterally bends neck and head; rotates head to same side Splenius capitis ligamentum nuchae and spines of C7-T6 vertebrae mastoid process and lateral end of the superior nuchal line dorsal primary rami of spinal nerves C2-C6 extends and laterally bends the neck and head, rotates head to the same side Splenius cervicis ligamentum nuchae and spines of C7-T6 vertebrae posterior tubercles of the transverse processes of C1-C3 vertebrae dorsal primary rami of spinal nerves C2-C6 extends and laterally bends neck and head, rotates head to the same side

25 MUSCLE OF THE BACK

26 MUSCLE OF THE BACK

27 MUSCLE OF THE BACK

28 MUSCLE OF THE BACK

29 MUSCLE OF THE ABDOMEN MUSCLE ORIGIN INSERTION INNERVATION ACTION Cremaster inguinal ligament forms thin network of muscle fascicles around the spermatic cord and testis (or around the distal portion of the round ligament of the uterus) Dartos External abdominal oblique Interfoveolar subcutaneous connective tissue of the scrotum and the penis (or labium majus and clitoris) lower 8 ribs transversus abdominis fibers that lie superficial to the inferior epigastric vessels skin of the scrotum and penis (or labium majus and clitoris) linea alba, pubic crest & tubercle, anterior superior iliac spine & anterior half of iliac crest anterior lamina of femoral sheath, immediately distal to origin of inferior epigastric vessels genital branch of the genitofemoral nerve postganglionic sympathetic nerve fibers arriving via the ilioinguinal nerve and the posterior scrotal nerve intercostal nerves 7-11, subcostal, iliohypogastric and ilioinguinal nerves iliohypogastric and ilioinguinal nerves elevates testis (not well developed in females) elevates testis (tenses the skin of the pudendal region in the female) flexes and laterally bends the trunk compresses abdominal contents

30 MUSCLE OF THE ABDOMEN MUSCLE ORIGIN INSERTION INNERVATION ACTION Internal abdominal oblique Oblique, external abdominal Oblique, internal abdominal Psoas major thoracolumbar fascia, anterior 2/3 of the iliac crest, lateral 2/3 of the inguinal ligament lower 8 ribs thoracolumbar fascia, anterior 2/3 of the iliac crest, lateral 2/3 of the inguinal ligament bodies and transverse processes of lumbar vertebrae lower 3 or 4 ribs, linea alba, pubic crest linea alba, pubic crest & tubercle, anterior superior iliac spine & anterior half of iliac crest lower 3 or 4 ribs, linea alba, pubic crest lesser trochanter of femur (with iliacus) via iliopsoas tendon intercostal nerves 7-11, subcostal, iliohypogastric and ilioinguinal nerves intercostal nerves 7-11, subcostal, iliohypogastric and ilioinguinal nerves intercostal nerves 7-11, subcostal, iliohypogastric and ilioinguinal nerves branches of the ventral primary rami of spinal nerves L2-L4 flexes and laterally bends the trunk flexes and laterally bends the trunk flexes and laterally bends the trunk flexes the thigh; flexes & laterally bends the lumbar vertebral column

31 MUSCLE OF THE ABDOMEN MUSCLE ORIGIN INSERTION INNERVATION ACTION Psoas minor Pyramidalis Quadratus lumborum Rectus abdominis Transversus abdominis bodies of the T12 & L1 vertebrae pubis, anterior to the rectus abdominis posterior part of the iliac crest and the iliolumbar ligament pubis and the pubic symphysis lower 6 ribs, thoracolumbar fascia, anterior 3/4 of the iliac crest, lateral 1/3 of inguinal ligament iliopubic eminence at the line of junction of the ilium and the superior pubic ramus branches of the ventral primary rams of spinal nerves L1-L2 flexes & laterally bends the lumbar vertebral column linea alba subcostal nerve draws the linea alba inferiorly transverse processes of lumbar vertebrae 1-4 and the 12th rib xiphoid process of the sternum and costal cartilages 5-7 linea alba, pubic crest and pecten of the pubis subcostal nerve and ventral primary rami of spinal nerves L1-L4 intercostal nerves 7-11 and subcostal nerve intercostal nerves 7-11, subcostal, iliohypogastric and ilioinguinal nerves laterally bends the trunk, fixes the 12th rib flexes the trunk compresses the abdomen

32 MUSCLE OF THE ANTERIOR ABDOMEN

33 MUSCLE OF THE ANTERIOR ABDOMEN

34 MUSCLE OF THE ANTERIOR ABDOMEN

35 MUSCLE OF THE ANTERIOR ABDOMEN

36 MUSCLE OF THE ANTERIOR ABDOMEN

37 MUSCLE OF THE ANTERIOR ABDOMEN

38 NEXT MEETING Muscles of Perineum Muscles of the upper and lower extremities Clinical Considerations

39 MUSCLES OF THE PELVIC WALLS MUSCLE ORIGIN INSERTION INNERVATION ACTION Obturator internus flat, fan-shaped muscle Piriformis triangular Anterolateral wall of true pelvis (deep surface of obturator membrane and surrounding bone) Anterior surface of sacrum between anterior sacral foramina Medial surface of greater trochanter of femur Medial side of superior border of greater trochanter of femur Nerve to obturator internus L5, S1 Branches from L5, S1 and S2 Lateral rotation of the extended hip joint; abduction of flexed hip Lateral rotation of the extended hip joint; abduction of flexed hip

41 MUSCLES OF THE PELVIC DIAPHRAGM MUSCLE ORIGIN INSERTION INNERVATION ACTION Levator ani Posterior pubis and ischial spine (In a line around the pelvic wall beginning on the posterior aspect of the pubic bone and extending across the obturator internus muscle as a tendinous arch (thickening of the obturator internus fascia) to the ischial spine) Sacrum and Coccyx The anterior part is attached to the superior surface of the perineal membrane; the posterior part meets its partner on the other side at the perineal body, around the anal canal, and along the anococcygeal ligament Branches direct from the ventral ramus of S4, and by the inferior rectal branch of the pudendal nerve (S2 to S4) Elavates anus, supports pelvic viscera, contributes to the formation of the pelvic floor, reinforces the external anal sphincter and in women, functions as a vaginal sphincter Coccygeus Ischial spine and pelvic surface of the sacrospinous ligament Lateral margin of coccyx, and related border of sacrum Branches from the anterior rami of S3 and S4 Contributes to the formation of the pelvic floor, which supports the pelvic

43 MUSCLES WITHIN THE DEEP PERINEAL POUCH MUSCLE ORIGIN INSERTION INNERVATION ACTION Deep transverse perineal Compressor urethrae (in women only) Sphincter urethrovaginalis (in women only) Medial aspect of ischial ramus Ischiopubic ramus on each side Perineal body Perineal body Blends with partner on other side anterior to the urethra Passes forward lateral to the vagina to blend with partner on other side anterior to the urethra Perineal branches of the pudendal nerve (S2 to S4) Perineal branches of the pudendal nerve (S2 to S4) Perineal branches of the pudendal nerve (S2 to S4) Stabilizes the position of the perineal body Functions as an accessory sphincter of the urethra Functions as an accessory sphincter of the urethra (also may facilitate closing the vagina)

44 MUSCLES WITHIN THE DEEP PERINEAL POUCH MUSCLE ORIGIN INSERTION INNERVATION ACTION External urethral sphincter Deep transverse perineal Compressor urethrae (in women only) Sphincter urethrovaginalis (in women only) From the inferior ramus of the pubis on each side and adjacent walls of the deep perineal pouch Medial aspect of ischial ramus Ischiopubic ramus on each side Perineal body Surrounds membranous part of urethra Perineal body Blends with partner on other side anterior to the urethra Passes forward lateral to the vagina to blend with partner on other side anterior to the urethra Perineal branches of the pudendal nerve (S2 to S4) Perineal branches of the pudendal nerve (S2 to S4) Perineal branches of the pudendal nerve (S2 to S4) Perineal branches of the pudendal nerve (S2 to S4) Compresses the membranous urethra; relaxes during micturition Stabilizes the position of the perineal body Functions as an accessory sphincter of the urethra Functions as an accessory sphincter of the urethra (also may facilitate closing the vagina)

46 MUSCLES IN GASTROINTESTINAL SYSTEM MUSCLE ORIGIN INSERTION INNERVATION ACTION External anal sphincter Coccyx Central tendon of perineum Puborectalis Internal anal sphincter Iliococcygeus posterior aspect of the body of the pubis unites with the puborectalis m. of other side posterior to the rectum inferior rectal nerves (from the pudendal nerve) branches of the ventral primary rami of spinal nerves S3-S4 encircles the anal canal encircles the anal canal parasympathetic fibers from S4 arcus tendineus levator ani and the ischial spine anococcygeal raphe and the coccyx branches of the ventral primary rami of spinal nerves S3-S4 Keeps orifice of anal canal closed draws the distal rectum forward and superiorly; aids in voluntary retention of feces constricts the anal canal elevates the pelvic floor

48 MUSCLES OF THE UPPER EXTREMITY MUSCLE ORIGIN INSERTION INNERVATION ACTION Trapezius Deltoid Levator scapulae Rhomboid minor Rhomboid major Superior nuchal line, external occipital protuberance, medial margin of the ligamentum nuchae, spinous processes of CVII to TXII and the related supraspinous ligaments Inferior edge of the crest of the spine of the scapula, lateral margin of the acromion, anterior border of lateral onethird of clavicle Transverse processes of CI and CII vertebrae and posterior tubercles of transverse processes of CIII and CIV vertebrae Lower end of ligamentum nuchae and spinous processes of CVII and TI vertebrae Spinous processes of TII TV vertebrae and intervening supraspinous ligaments Superior edge of the crest of the spine of the scapula, acromion, posterior border of lateral one-third of clavicle Motor spinal part of accessory nerve (XI). Sensory (proprioception) anterior rami of C3 and C4 Powerful elevator of the scapula; rotates the scapula during abduction of humerus above horizontal; middle fibers retract scapula; lower fibers depress scapula Deltoid tuberosity of humerus Axillary nerve (C5, C6) Major abductor of arm (abducts arm beyond initial 15 done by supraspinatus); clavicular fibers assist in flexing the arm; posterior fibers assist in extending the arm Posterior surface of medial border of scapula from superior angle to root of spine of the scapula Posterior surface of medial border of scapula at the root of the spine of the scapula Posterior surface of medial border of scapula from the root of the spine of the scapula to the inferior angle Branches directly from anterior rami ofc3 and C4spinal nerves and by branches (C5) from the dorsal scapular nerve Dorsal scapular nerve (C4, C5) Dorsal scapular nerve (C4, C5) Elevates the scapula Elevates and retracts the scapula Elevates and retracts the scapula

50 MUSCLES OF THE UPPER EXTREMITY MUSCLE ORIGIN INSERTION INNERVATION ACTION Supraspinatus Medial two-thirds of the supraspinous fossa of the scapula and the deep fascia that covers the muscle Most superior facet on the greater tubercle of the humerus Suprascapular nerve (C5, C6) Rotator cuff muscle; initiation of abduction of arm to 15 at glenohumeral joint Infraspinatus Medial two-thirds of the infraspinous fossa of the scapula and the deep fascia that covers the muscle Middle facet on posterior surface of the greater tubercle of the humerus Suprascapular nerve (C5, C6) Rotator cuff muscle; lateral rotation of arm at the glenohumeral joint Teres minor Upper two-thirds of a flattened strip of bone on the posterior surface of the scapula immediately adjacent to the lateral border of the scapula Inferior facet on the posterior surface of the greater tubercle of the humerus Axillary nerve (C5, C6) Rotator cuff muscle; lateral rotation of arm at the glenohumeral joint Teres major Elongate oval area on the posterior surface of the inferior angle of the scapula Medial lip of the intertubercular sulcus on the anterior surface of the humerus Inferior subscapular nerve (C5, C6,C7) Medial rotation and extension of the arm at the glenohumeral joint Long head of triceps brachii Infraglenoid tubercle on scapula Common tendon of insertion with medial and lateral heads on the olecranon process of ulna Radial nerve (C6, C7, C8) Extension of the forearm at the elbow joint; accessory adductor and extensor of the arm at the glenohumeral joint

52 MUSCLES OF THE UPPER EXTREMITY MUSCLE ORIGIN INSERTION INNERVATION ACTION Pectoralis major Clavicular head anterior surface of medial half of clavicle; sternocostal head anterior surface of sternum; first seven costal cartilages; sternal end of sixth rib; aponeurosis of external oblique Lateral lip of intertubercular sulcus of humerus Medial and lateral pectoral nerves; clavicular head (C5, C6); sternocostal head (C6, C7, C8, T1) Flexion, adduction, and medial rotation of arm at glenohumeral joint; clavicular head flexion of extended arm; sternocostal head extension of flexed arm Subclavius First rib at junction between rib and costal cartilage Groove on inferior surface of middle one-third of clavicle Nerve to subclavius (C5, C6) Pulls tip of shoulder down; pulls clavicle medially to stabilize sternoclavicular joint Pectoralis minor Anterior surfaces and superior borders of ribs III to V; and from deep fascia overlying the related intercostal spaces Coracoid process of scapula (medial border and upper surface) Medial pectoral nerve (C5, C6,C7, C8, T1) Pulls tip of shoulder down; protracts scapula Serratus anterior Lateral surfaces of upper 8 9 ribs and deep fascia overlying the related intercostal spaces Costal surface of medial border of scapula Long thoracic nerve (C5, C6, C7) Protraction and rotation of the scapula; keeps medial border and inferior angle of scapula opposed to thoracic wall

56 MUSCLES OF THE UPPER EXTREMITY MUSCLE ORIGIN INSERTION INNERVATION ACTION Subscapularis Medial two-thirds of subscapular fossa Lesser tubercle of humerus Upper and lower subscapular nerves (C5, C6, (C7)) Rotator cuff muscle; medial rotation of the arm at the glenohumeral joint Teres major Elongate oval area on the posterior surface of the inferior angle of the scapula Medial lip of the intertubercular sulcus on the anterior surface of the humerus Lower subscapular nerve (C5, C6, C7) Medial rotation and extension of the arm at the glenohumeral joint Latissimus dorsi Spinous processes of lower six thoracic vertebrae and related interspinous ligaments; via the thoracolumbar fascia to the spinous processes of the lumbar vertebrae, related interspinous ligaments, and iliac crest; lower 3 4 ribs Floor of intertubercular sulcus Thoracodorsal nerve (C6, C7, C8) Adduction, medial rotation, and extension of the arm at the glenohumeral joint Long head of triceps brachii Infraglenoid tubercle on scapula Common tendon of insertion with medial and lateral heads on the olecranon process of ulna Radial nerve (C6, C7, C8) Extension of the forearm at the elbow joint; accessory adductor and extensor of the arm at the

59 MUSCLES OF THE UPPER EXTREMITY MUSCLE ORIGIN INSERTION INNERVATION ACTION Biceps brachii Long head supraglenoid tubercle of scapula; short head apex of coracoid process Tuberosity of radius Musculocutaneous nerve (C5, C6) Powerful flexor of the forearm at the elbow joint and supinator of the forearm; accessory flexor of the arm at the glenohumeral joint Coracobrachialis Apex of coracoid process Linear roughening on midshaft of humerus on medial side Musculocutaneous nerve ( C5, C6, C7) Flexor of the arm at the glenohumeral joint; adducts arm

61 Quadrate tubercle on the MUSCLES OF THE LOWER EXTREMITY (GLUTEAL REGION) MUSCLE ORIGIN INSERTION INNERVATION ACTION Piriformis Anterior surface of sacrum between anterior sacral foramina Medial side of superior border of greater trochanter of femur Branches from S1 ands2 Laterally rotates the extended femur at hip joint; abducts flexed femur at hip joint Obturator internus Anterolateral wall of true pelvis; deep surface of obturator membrane and surrounding bone Medial side of greater trochanter of femur Nerve to obturator internus (L5,S1) Laterally rotates the extended femur at hip joint; abducts flexed femur at hip joint Gemellus superior External surface of ischial spine Along length of superior surface of the obturator internus tendon and into the medial side of greater trochanter of femur with obturator internus tendon Nerve to obturator internus (L5,S1) Laterally rotates the extended femur at hip joint; abducts flexed femur at hip joint Gemellus inferior Upper aspect of ischial tuberosity Along length of inferior surface of the obturator internus tendon and into the medial side of greater trochanter of femur with obturator internus tendon Nerve to quadratus femoris (L5, S1) Laterally rotates the extended femur at hip joint; abducts flexed femur at hip joint

62 MUSCLES OF THE LOWER EXTREMITY (GLUTEAL REGION) MUSCLE ORIGIN INSERTION INNERVATION ACTION Gemellus inferior Upper aspect of ischial tuberosity Along length of inferior surface of the obturator internus tendon and into the medial side of greater trochanter of femur with obturator internus tendon Nerve to quadratus femoris (L5, S1) Laterally rotates the extended femur at hip joint; abducts flexed femur at hip joint Quadratus femoris Lateral aspect of the ischium just anterior to the ischial tuberosity Quadrate tubercle on the intertrochanteric crest of the proximal femur Nerve to quadratus femoris (L5, S1) Laterally rotates femur at hip joint Gluteus minimus External surface of ilium between inferior and anterior gluteal lines Linear facet on the anterolateral aspect of the greater trochanter Superior gluteal nerve (L4, L5, S1) Abducts femur at hip joint; holds pelvis secure over stance leg and prevents pelvic drop on the opposite swing side during walking; medially rotates thigh Gluteus medius External surface of ilium between anterior and posterior gluteal lines Elongate facet on the lateral surface of the greater trochanter Superior gluteal nerve (L4, L5, S1) Abducts femur at hip joint; holds pelvis secure over stance leg and prevents pelvic drop on the opposite swing side during walking; medially rotates thigh

65 MUSCLES OF THE LOWER EXTREMITY (ANTERIOR COMP. THIGH) MUSCLE ORIGIN INSERTION INNERVATION ACTION Psoas major Posterior abdominal wall (lumbar transverse processes, intervertebral discs, and adjacent bodies from TXII to LV and tendinous arches between these points) Lesser trochanter of femur Anterior rami (L1, L2, L3) Flexes the thigh at the hip joint Iliacus Posterior abdominal wall (iliac fossa) Lesser trochanter of femur Femoral nerve (L2, L3) Flexes the thigh at the hip joint Vastus medialis Femur medial part of intertrochanteric line, pectineal line, medial lip of the linea aspera, medial supracondylar line Quadriceps femoris tendon and medial border of patella Femoral nerve (L2,L3, L4) Extends the leg at the knee joint Vastus intermedius Femur upper two-thirds of anterior and lateral surfaces Quadriceps femoris tendon, lateral margin of patella, and lateral condyle of tibia Femoral nerve (L2,L3, L4) Extends the leg at the knee joint Vastus lateralis Femur lateral part of intertrochanteric line, margin of greater trochanter, lateral margin of gluteal tuberosity, lateral lip of the linea aspera Quadriceps femoris tendon and lateral margin of patella Femoral nerve (L2,L3, L4) Extends the leg at the knee joint Rectus femoris Straight head originates from the anterior inferior iliac spine; reflected head originates from the ilium just superior to the acetabulum Quadriceps femoris tendon Femoral nerve (L2, L3, L4) Flexes the thigh at the hip joint and extends the leg at the knee joint Medial surface of tibia just Flexes the thigh at the hip

69 MUSCLES OF THE LOWER EXTREMITY (MEDIAL COMP. THIGH) MUSCLE ORIGIN INSERTION INNERVATION ACTION Gracilis Pectineus Adductor longus Adductor brevis A line on the external surfaces of the body of the pubis, the inferior pubic ramus, and the ramus of the ischium Pectineal line (pecten pubis) and adjacent bone of pelvis External surface of body of pubis (triangular depression inferior to pubic crest and lateral to pubic symphysis) External surface of body of pubis and inferior pubic ramus Adductor part Medial surface of proximal shaft of tibia Oblique line extending from base of lesser trochanter to linea aspera on posterior surface of proximal femur Linea aspera on middle one-third of shaft of femur Posterior surface of proximal femur and upper one-third of linea aspera Obturator nerve (L2, L3) Femoral nerve (L2, L3) Obturator nerve (anterior division) (L2, L3, L4) Obturator nerve (L2, L3) Posterior surface of proximal femur, linea Obturator nerve (L2, Adducts thigh at hip joint and flexes leg at knee joint Adducts and flexes thigh at hip joint Adducts and medially rotates thigh at hip joint Adducts and medially rotates thigh at hip joint Adducts and medially rotates thigh at hip

73 MUSCLES OF THE LOWER EXTREMITY (MEDIAL COMP. THIGH) MUSCLE ORIGIN INSERTION INNERVATION ACTION Biceps Semitendinosus Semimembranosus Long head inferomedial part of the upper area of the ischial tuberosity; short head lateral lip of linea aspera Inferomedial part of the upper area of the ischial tuberosity Superolateral impression on the ischial tuberosity Head of fibula Sciatic nerve (L5, S1, S2] Medial surface of proximal tibia Groove and adjacent bone on medial and posterior surface of medial tibial condyle Sciatic nerve (L5,S1,S2) Sciatic nerve (L5, S1,S2) Flexes leg at knee joint; extends and laterally rotates thigh at hip joint and laterally rotates leg at knee joint Flexes leg at knee joint and extends thigh at hip joint; medially rotates thigh at hip joint and leg at knee joint Flexes leg at knee joint and extends thigh at hip joint; medially rotates thigh at hip joint and leg at knee joint

Scapula Spine Lateral edge of clavicle. Medial border Scapula. Medial border of Scapula, between superior angle and root of spine. Scapula.

Scapula Spine Lateral edge of clavicle. Medial border Scapula. Medial border of Scapula, between superior angle and root of spine. Scapula. Muscle attachments and actions answer sheet Muscle Origins insertions Movements Joints crossed Trapezius Base of skull Spinous process of C7 Thoracic Spine Lateral edge of clavicle Elevation Retraction