Skeletal Myology

FromStudent 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)

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.

DeltoidOrigin: 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 ( )

AdductorMagnus

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 • Function/Action: Flexes and medially rotates knee. Extends hip• 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.• Nerve Supply: Posterior division of femoral nerve (L3, 4)

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

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 FrontalBone.* The Frontalis are joined together above the rootof the nose and to the top ofThe 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 locatedAlong the back of the head Across the Occipital Bone.• The Occipitalis is joined Together by tendinous fiberRunning from the OccipitalBone.

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 hipabduction 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

MasseterOrigin: 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)