Adapted from Martini Human Anatomy 7th ed. Chapter 10 The Muscular System Axial Musculature Introduction The skeletal muscle of the body can be subdivided into: Axial musculature Muscles that position the head and vertebral column Muscles that move the rib cage Appendicular musculature Muscles that stabilize or move the appendicular skeleton The axial muscles can be placed into four groups based on location or function Muscles of the head and neck Muscles of the vertebral column Oblique and rectus muscles Muscles of the pelvic floor Muscles of the Head and Neck Can be subdivided into several different groups Muscles of facial expression Extraocular muscles Muscles of mastication Muscles of the tongue Muscles of the pharynx Muscles of the anterior neck Muscles of Facial Expression (Mouth) Orbicularis oris Zygomaticus major and minor Risorius Mentalis Depressor labii inferioris Depressor anguli oris Levator anguli oris Buccinator Depressor labii superioris Muscles of Facial Expression (Eye) Page 1 of 6 BIOL_218_F_2011_Lecture Outline Ch 10
Corrugator supercilii Levator palpebrae superioris Orbicularis oculi Muscles of Facial Expression (Nose) Procerus Nasalis Muscles of Facial Expression (Scalp) Occipitofrontalis Frontal belly (frontalis) Occipital belly (occipitalis) Temporoparietalis Muscles of Facial Expression (Neck) Platysma Extra-ocular Muscles Extrinsic eye muscles (muscles that control eye movement) Medial and lateral rectus muscles Superior and inferior rectus muscles Superior and inferior oblique muscles Extra-ocular Muscles Eye movements Lateral rectus: rotates the eye laterally Medial rectus: rotates the eye medially Superior rectus: rotates the eye upward Inferior rectus: rotates the eye downward Superior oblique: rotates the eye downward and laterally Inferior oblique: rotates the eye upward and laterally Muscles of Mastication Masseter Temporalis Pterygoids Muscles of the Tongue Genioglossus Page 2 of 6 BIOL_218_F_2011_Lecture Outline Ch 10
Hyoglossus Palatoglossus Styloglossus Muscles of the Pharynx Pharyngeal constrictors Superior constrictor Middle constrictor Inferior constrictor Muscles of the Pharynx (continued) Laryngeal elevators Palatopharyngeus Stylopharyngeus Muscles of the Pharynx (continued) Palatal muscles Levator veli palatini Tensor veli palatini Anterior Muscles of the Neck Digastric Mylohyoid (deep to the digastric) Geniohyoid (deep to the mylohyoid) Stylohyoid Anterior Muscles of the Neck (continued) Omohyoid Sternohyoid (deep to the omohyoid) Sternothyroid (deep to the sternohyoid) Thyrohyoid (attached to the sternothyroid and hyoid bone) Sternocleidomastoid Muscles of the Vertebral Column Back muscles form three distinct layers Superficial layer (extrinsic back muscles): move the neck Intermediate layer (extrinsic back muscles): move the vertebral column Deep layer (intrinsic back muscles): interconnect the vertebrae Examples of the extrinsic back muscles Page 3 of 6 BIOL_218_F_2011_Lecture Outline Ch 10
Superficial layer of extrinsic muscles Trapezius Latissimus dorsi Levator scapulae Rhomboid muscle Example of the extrinsic back muscles Intermediate layer of extrinsic muscles Serratus posterior The Deep Layer (or intrinsic back muscles) Can be further subdivided into: Superficial intrinsic Intermediate intrinsic Deep intrinsic Example of Superficial Intrinsic Back Muscles Splenius muscles Examples of Intermediate Intrinsic Back Muscles Erector spinae (group of three muscles) Spinalis thoracis (most medial of the three) Longissimus thoracis Iliocostalis lumborum (most lateral of the three) Examples of Deep Intrinsic Back Muscles Semispinalis Multifidus Rotatores Interspinales Intertransversarii Spinal Flexors Longus capitis Longus colli The above two muscles rotate or flex the neck Quadratus lumborum Flexes the vertebral column laterally Page 4 of 6 BIOL_218_F_2011_Lecture Outline Ch 10
These muscles can be grouped in this manner: Cervical muscles Thoracic muscles Abdominal muscles Cervical oblique muscles Scalene muscles (anterior, middle, and posterior scalenes) Elevate the ribs and also flex the neck Thoracic oblique muscles External intercostals: elevate the ribs Internal intercostals: depress the ribs Transversus thoracis: depresses the ribs Serratus posterior Superior serratus posterior: elevates ribs and enlarges thoracic cavity Inferior serratus posterior: depresses ribs and opposes diaphragm contraction thus decreasing thoracic size Abdominal oblique muscles External oblique: rotates the vertebral column Internal oblique: rotates the vertebral column Transversus abdominis: compresses the abdomen Cervical Rectus Muscles Geniohyoid Omohyoid Sternohyoid Thyrohyoid Thoracic Rectus Muscles Diaphragm muscle Expands the thoracic cavity for inhalation Abdominal Rectus Muscles Rectus abdominis Flexes the vertebral column Divided longitudinally by the linea alba Divided transversally by the tendinous inscriptions Page 5 of 6 BIOL_218_F_2011_Lecture Outline Ch 10
Muscles of the Perineum and Pelvic Diaphragm Main functions Support the organs of the pelvic cavity Flex the joints of the sacrum and coccyx Control the movement of material through the urethra and anus The Perineum (pelvic floor) Divided into two triangles Urogenital triangle Anal triangle The two triangles are separated by: Superficial transverse perineal muscle Muscles of the Pelvic Floor Superficial urogenital triangle area Superficial transverse perineal Ischiocavernosus Bulbospongiosus Superficial anal triangle area Superficial transverse perineal Gluteus maximus External anal sphincter Muscles of the Pelvic Floor Deep urogenital triangle area Deep transverse perineal Deep anal triangle area Coccygeus Iliococcygeus Pubococcygeus Page 6 of 6 BIOL_218_F_2011_Lecture Outline Ch 10