Skeletal Myology From Student Research

Gluteus Maximus

Gluteus Maximus Number-two Origin-posterior aspect of dorsal ilium posterior to posterior gluteal line Insertions-primarily in fascia lata at the illiotibial band, also in the gluteal tuberosity on posterior femoral side Action-major extension of hip joint, assists in laterally rotating the thigh Innervation-inferior gluteal nerve (L5, S1, S2) Other facts- largest of the gluteal muscle, allows people to walk upright

Gluteus Medius

Gluteus Medius Number-two Origin-dorsal ilium inferior to iliac crest Insertion-lateral and superior surfaces of greater trochanter Action-major abductor of thigh Innervation- superior gluteal nerve (L4, L5, S1) Other facts- as you walk the gluteus medius muscles supports full upper body weight and every one pound of extra body weight adds two pounds to the workload, also stabilizes the hips

Gluteus Minimus

Gluteus Minimus Number-two Origin-dorsal ilium between inferior and anterior gluteal lines Insertion-anterior surface of greater trochanter Innervation-superior gluteal nerve (L4, L5, S1) Action-abduction of the hip Other facts- smallest gluteal muscle

Subscapularis

Origin: Entire anterior surface of the subscapularis fossa. Insertion: the lesser tuberosity of humerus and capsule of shoulder joint. Action: rotates the head of the humerus medially(internal rotation); when the arm is raised, it draws the humerus forward and downward. Innervation: Subscapular nerve (C5,C6)

Origin- superolateral surfaces of upper 8 or 9 ribs at the side of chest Insertion- Vertebral border of scapula Innervation – Long Thoracic Nerve (C5,C6,C7)

Gastrocnemis Origin: just superior to articular surfaces of the lateral and medial condyles of the femur. Insertion: posterior calcaneus via the Achilles Tendon Action: plantar flexes the foot, and it also flexes the knee. Innervation: tibial nerve (S1 - S2)

Soleus Origin: posterior superior fibula and tibia Insertion: Posterior calcaneous via Achilles Tendon Action: plantar flexion. Innervation:tibial nerve, (L5-S2) Soleus

Triceps Brachii

Origin Long Head- From infraglenoid tuberosity of the scapula Lateral Head- From posterior and lateral surface of the Humerus Medial Head- From lower posterior surface of the Humerus Insertion: Upper posterior surface of the olecranon and the deep forearm fascia Action: extension of the forearm, stabilize shoulders Innervation: radial nerve

Levator Scapulae

Origin: Posterior tubercles of transverse processes of C1- C4 Insertion: Upper part of the medial border of scapula Action: Raises medial border of scapula Innervation: Anterior primary rami of C3 and C4 and dorsal scapular nerve (C5)

Coracobrachialis Origin: Coracoid process of scapula. Insertion: Mid-medial surface of humerus. Action: Flexes and adducts arm at shoulders. Innervation: musculoskeletal nerve and partly by the radial nerve.

Deltoid Origin: anterior surface of lateral clavicle, acromion process and spine of scapula. Insertion: Deltoid tuberosity of humerus Action: flexes & medially rotation, abduction Innervation: Axillary nerve

Biceps Brachii

Biceps Brachii

Biceps Brachii Origin: supraglenoid tubercle of the scapula Insertion: Radial tuberosity and aponeurosis of forearm Action: flexes elbow Innervation: Musculocutaneous nerve

Brachialis

Origin: anterior, distal half of the humerus Insertion: Coroniod process and tuberosity of ulna. Function: Flexes forearm at the elbow. Innervation: Musculocutaneous nerve

Internal Abdominal Oblique Origin: anterior iliac crest, lateral half of inguinal ligament, and thoracolumbar fascia Insertion: costal cartilages of ribs 8-12: abdominal aponeurosis to linea alba Innervation: lower intercostal nerves, as well as the iliohypogastric nerve and the ilioinguinal nerve Action: flexes, rotates and laterally flexes torso at lower thoracic and upper lumbar vertebral levels, compresses abdomen

External Abdominal Oblique Origin: external surfaces of ribs 5-12 Insertion: anterior iliac crest and abdominal aponeurosis to linea alba Actions: flexes vertebral column (draws thorax downward), rotates vertebral column (torso), laterally flexes vertebral column (torso), compress abdomen. Innervation: The external oblique muscle is innervated by ventral branches of the lower 6 intercostal (thoracoabdominal) nerves and the subcostal nerve on each side.

Rhomboideus Major Origin: Spinous process of T2-T5 vertebrae. Insertion: Medial border of scapula inferior to spine of scapula. Actions: Retracts and elevates the medial border of scapula while it downwardly rotates the lateral angle. Innervation: Dorsal scapular nerve (C5).

External Anal Sphincter Origin: perineal body or central tendinous point of the perineum Insertion: encircles the anal canal; superficial fibers attach to coccyx. Action: constricts the anal canal Innervation: inferior rectal nerves (from the pudendal nerve)

Rectus Femoris Origin: anterior inferior iliac spine Insertion: Tibial Tuberosity via patellar tendon, patella and patellar ligament. Action: Extends leg at knee, flexes thigh at hip Innervation: Femoral nerve (L2-L3)

Biceps Femoris Origin: Ischial Tuberosity Insertion: Head of fibula and lateral condyle of tibia. Action: : Extends femur, flexes knee, laterally rotates leg if knee is flexed Innervation: Tibial part of sciatic nerve (L5,S1,S2)

Biceps Femoris

Buccinator

Buccinator Origin: Alveolar processes of maxilla and mandible Insertion: Orbicularis Oris Function: Compresses cheek into the teeth for chewing. Innervation: Deep buccal branches of the facial nerve (C.N. VII)

Zygomaticus

Zygomaticus Origin: Anterior surface of zygomatic bone Insertion: Fascia and fibers of orbicularis oris at angle of mouth Function: Elevates and draws angle of mouth laterally Innervation: zygomatic and buccal branches of the facial nerve (VII)

Adductor Longus Origin: Insertion: middle third of the linea aspera. Function: adduct and laterally rotate the femur. Innervation: obturator nerve ( )

Adductor Magnus and Longus

Adductor Magnus Origin: Insertion: Adductor tubercle on the medial condyle of the femur and linea aspera Action: Medial rotator when the leg is rotated outwards and flexed, extends the hip joint Innervation: posterior division of the obturator nerve ( ) and tibial nerve.

Pronator Teres

Pronator Teres Origin: Medial Epicondyle (Common Flexor Tendon) and Coronoid Process of Ulna Insertion: Middle of the lateral surface of the shaft of the radius. Function– Pronation and flexion of the forearm Innervation: Median Nerve

Pronator Quadratus

Pronator Quadratus Origin: Medial, anterior surface of the Ulna Insertion: Lateral, anterior surface of the Radius Function: Innervation: Median Nerve (Anterior interosseous Nerve)

Hamstrings Muscle Group There are 2 groups of Hamstring Muscles (3 muscles in each leg) They are located on the posterior thigh. Semitendinosus: Origin: upper in quadrant of posterior surface of ischial tuberosity Insertion: Upper medial shaft of tibia below gracilis Function/Action: Flexes and medially rotates knee. Extends hip Nerve Supply: Tibial portion of sciatic nerve. Semimembranosus: Origin: upper outer quadrant of posterior surface of ischial tuberosity Insertion: medial condyle of tibia below articular margin, fascia over popliteus and oblique popliteal ligament Nerve Supply: Tibial portion of sciatic nerve (L5, S1)

Biceps Femoris Origin: Long head; upper inner quadrant of posterior surface of ischial tuberosity. Short head; middle third of linea aspera, lateral supracondylar ridge of femur. Insertion: Styloid process of head of fibula. Lateral collateral ligament and lateral tibial condyle. Action: Flexes and laterally rotates knee. Long head extends hip. Nerve Supply: Long head; tibial portion of sciatic nerve. Short head; common peroneal portion of sciatic nerve (both L5, S1)

Quadriceps Muscle Group 2 groups of Quadricep Muscles ( 4 muscles in each leg) They cover the front and sides of the thigh. Rectus Femoris: Origin: Straight head; anterior inferior iliac spine. Reflected head; ilium above acetabulum. Insertion: Quadriceps tendon to patella, via ligamentum patellae into tubercle of tibia. Function/Action: Extends leg at knee. Flexes thigh at hip. Nerve Supply: Posterior division of femoral nerve (L3, 4) Vastus Lateralis (Externus): Origin: Upper intertrochanteric line, base of greater trochanter, lateral linea aspera, lateral supracondylar ridge and lateral intermuscular septum. Insertion: Lateral quadriceps tendon to patella, via ligamentum patellae into tubercle of tibia. Function/Action: Extends knee.

Quadriceps continued... Vastus Intermedius: Origin: Anterior and lateral shaft of femur. Insertion: Quadriceps tendon to patella, via ligamentum patellae into tubercle of tibia. Function/Action: Extends knee Nerve Supply: Posterior division of femoral nerve (L3,4) Vastus Medialis (Internus): Origin: Lower intertrochanteric line, spiral line, medial linea aspera and medial intermuscular septum. Insertion: Medial quadriceps tendon to patella and directly into medial patella, via ligamentum patellae into tubercle of tibia. Function/Action: Extends knee, Stabilizes patella. Nerve Supply: Posterior division of femoral nerve (L3, 4)

Quadriceps Muscles

Orbicularis Oculi ORIGIN - medial orbital margin and lacrimal sac INSERTION - Lateral palpebral raphe ACTION - Closes eyelids, aids drainage of tears NERVE - Temporal and zygomatic branches of facial nerve ( CN VII)

Orbicularis Oculi

Orbicularis Oris ORIGIN - Near midline on anterior surface of maxilla and mandible INSERTION - Mucous membrane of margin of lips and raphe with buccinator at modiolus ACTION - Narrows orifice of mouth, purses lips and puckers lip edges NERVE -

Orbicularis Oris

2 1 UNIQUE INFORMATION # ORBICULARIS OCULI -Facial paralysis affects the orbicularis oculi muscle. -The inability to close the eye causes it to dry out, resulting in pain or blindness. 2 ORBICULARIS ORIS -In common language, the orbicularis oris is often referred to as "the kissing muscle." 1

Frontalis * There is only 1 Frontalis muscle in the human body. * The Frontalis is located across the top of the Frontal Bone. * The Frontalis are joined together above the root of the nose and to the top of The Frontal Bone.

Frontalis Continued... Innervation: Facial nerve (CN VII) * Function: Facial expressions such as lifting skin of forehead and eyebrows.

Occipitalis There is only one Occipitalis muscle in the human body. The Occipitalis is located Along the back of the head Across the Occipital Bone. The Occipitalis is joined Together by tendinous fiber Running from the Occipital Bone.

Occipitalis continued... Function: Moving the scalp posterior Innervation: Facial Nerve (CN VII)

Peroneus Longus (Fibularis Longus) How Many: 2 Origin: Upper two thirds of lateral shaft of fibula Insertion: Tarsal and metatarsal bones Action: Plantar flexion and eversion of foot; also supports arch Innervation: Superficial peroneal nerve (L5, S1, S2)

Peroneus Tertius (Fibularis Tertius) How Many: 2 Origin: Anterior surface of fibula Insertion: Dorsal surface of the base of the 5th metatarsal Action: Dorsiflexion and eversion of foot Innervation: Deep peroneal nerve (L5, S1)

Tibialis Anterior and Posterior

Information... Origin: Anterior - upper half of lateral shaft of tibia and interosseous membrane. Posterior – Upper half of posterior shaft of tibia and upper half of fibula between medial nerve crest and interosseous border, and interosseous membrane. Insertion: Anterior – Inferomedial aspect of medical cuneiform and base of 1st metatarsal. Posterior – Tuberosity of navicular bone and all tarsal bones (except talus) and spring ligament. Action: Anterior – Extends and inverts foot at ankle & holds up medial longitudinal arch of foot. Posterior – Plantar flexes and inverts foot & supports medial longitudinal arch of foot.

Nerve supply Anterior: Peroneal, L4, L5, S1 Posterior: Tibial: L5, S1

Latissimus Dorsi Origin: Spinous process of vertebrae T7-L5, thoracolumbar fascia, iliac crest, inferior 3 or 4 ribs and inferior angle of scapula Insertion : Floor of the intertubercular groove of the humerus. Action: to abduct or extend and internally rotate the arm. Nerve supply: Thoracodorsal nerve. ‘The Swimmer’s Muscle’

Trapezious Origin: external occipital protuberance, nuchal ligament, medial superior nuchal line, spinous process of vertebrae C7-T12.) Insertion: Posterior border of the lateral third of the clavicle, acromion process and spine of scapula. Action: rotation, retraction , elevation and depression of scapula. Nerve supply: Accessory nerve (CN XI), cervical spinal nerves C3 & C4

Extensor Carpi Radialis Longus Origin: distal lateral supracondylar ridge Insertion: base of 2nd metacarpal Action: extends and abducts hand at wrist Nerve supply: Radial nerve, C6, C7

Extensor Carpi Radialis Brevis Origin: lateral epicondyle of humerus Insertion: base 3rd metacarpal (dorsal surface) Action: extends and abducts the wrist Nerve supply: C6, C7

The Gracilis Muscle Location: Groin Function: Responsible for hip abduction and assists knee flection

Sartorius Origin: anterior superior iliac spine Insertion: Function: Innervation:

Temporalis

Temporalis Origin: Temporal fossa between inferior temporal line (of the parietal bone) and infratemporal crest. Insertion: Coronoid process of the mandible and anterior ramus of the mandible. Action: Elevates mandible (closes jaw) and retracts mandible (horizontal fibers of posterior part of muscle). Nerve Supply: Mandibular division of Trigeminal nerve (CN V).

Masseter

Masseter Origin: superficial portion - zygomatic bone, deep - zygomatic arch. Insertion: ramus of the mandible Action: elevation of mandible (chew food) Nerve Supply: masseteric nerve of the mandibular division of the trigeminal nerve (CN V)