a&p ex3 muscle attachments/actions

Frontalis (action)

Elevates eyebrows; draws scalp forward and wrinkles skin of forehead.

Occipitalis (action)

Retracts scalp.

Orbicularis Oculi (action)

Closes eye in blinking, squinting, and sleep.

Orbicularis Oris (action)

Compresses lips to close mouth; purses lips.

Nasalis (action)

Elevates (flares) corners of nostrils.

Depressor Anguli Oris (action)

Draws corners of mouth laterally and downward ("tragedy mask").

Zygomaticus Major (action)

Elevates corner of mouth ("smile muscle").

Zygomaticus Major (attachment)

Zygomatic bone; skin and muscles of upper lip.

Zygomaticus Minor (action)

Elevates corner of mouth ("smile muscle").

Zygomaticus Minor (attachment)

Zygomatic bone; skin and muscles of upper lip.

Risorius (action)

Draws corner of lip laterally; tenses lips.

Buccinator (action)

Compresses cheek against teeth and gums during chewing.

Masseter (action)

Elevation and protraction of the mandible.

Masseter (attachment)

Zygomatic arch; mandibular angle and lateral ramus of mandible.

Temporalis (action)

Elevation, retraction, and lateral and medial excursion of the mandible.

Temporalis (attachment)

Temporal lines and temporal fossa of cranium; coronoid process and anterior border of mandible.

Sternocleidomastoid (action)

Unilateral action causes lateral flexion of neck and rotates head to face the opposite side; bilateral action flexes the neck.

Sternocleidomastoid (attachment)

Manubrium of sternum; medial 1/3 of clavicle; mastoid process; lateral half of superior nuchal line.

Scalenes Group (action)

Flexes neck forward; elevates ribs 1 and 2 during inspiration.

Scalenes Group (attachment)

Transverse processes of C1–C7; ribs 1–2.

Splenius Capitis (action)

Unilateral action rotates head to face the same side; bilateral action extends neck.

Splenius Capitis (attachment)

Mastoid process; cervical and thoracic vertebrae; all ribs.

Trapezius (action)

Extension and lateral flexion of neck; elevation, retraction, lateral (superior) rotation, elevation, and depression of the scapula.

Trapezius (attachment)

External occipital protuberance; superior nuchal line; spinous processes of vertebrae C7–T12; scapula and lateral clavicle.

Erector Spinae Group (Iliocostalis, Spinalis, Longissimus) (action)

Bilateral action: extension of the vertebral column; unilateral action: lateral flexion of vertebral column.

Erector Spinae Group (Iliocostalis, Spinalis, Longissimus) (attachment)

Nuchal ligament; ribs 3–12; thoracic and lumbar vertebrae; median sacral crests.

Transversospinalis Group (Multifidus, Rotatores, Semispinalis Group) (action)

Bilateral action: extension of the vertebral column; unilateral action: lateral flexion and rotation of vertebral column.

Transversospinalis Group (Multifidus, Rotatores, Semispinalis Group) (attachment)

Spinous processes and transverse processes of vertebrae; sacrum (most inferior attachment); occipital bone (most superior attachment).

Diaphragm (action)

Contraction increases volume of thoracic cavity, contributing to inspiration.

External Intercostals (action)

Elevation of ribs increases volume of thoracic cavity for inspiration.

Internal Intercostals (action)

Depression of the ribs decreases volume of thoracic cavity for forced expiration.

External Oblique (action)

Compresses abdomen; flexes/stabilizes vertebral column during lifting; unilateral contraction causes contralateral rotation.

External Oblique (attachment)

Ribs 5–12; iliac crest; pubic symphysis and superior ramus of pubis.

Transversus Abdominis (action)

Compresses abdominal wall; used in forced expiration.

Rectus Abdominis (action)

Flexion of vertebral column; compresses abdominal wall; used in forced expiration.

Rectus Abdominis (attachment)

Pubic symphysis and superior ramus of pubis; xiphoid process; costal cartilages 5–7.

Trapezius (action)

Extension and lateral flexion of neck; elevation, retraction, lateral (superior) rotation, elevation, and depression of the scapula.

Trapezius (attachment)

External occipital protuberance; superior nuchal line; spinous processes of vertebrae C7–T12; scapula and lateral clavicle.

Levator Scapulae (action)

Elevation and medial (inferior) rotation of scapula.

Rhomboid Major (action)

Retraction, elevation, and medial (inferior) rotation of scapula.

Rhomboid Minor (action)

Retraction, elevation, and medial (inferior) rotation of scapula.

Pectoralis Minor (action)

Protraction and depression of scapula.

Pectoralis Minor (attachment)

Ribs 3–5; coracoid process of scapula.

Serratus Anterior (action)

Lateral (superior) rotation and protraction of scapula.

Deltoid (action)

Abduction, flexion, extension, medial rotation, and lateral rotation of the arm.

Pectoralis Major (action)

Flexion, adduction, and medial rotation of the arm.

Pectoralis Major (attachment)

Medial clavicle; sternum; costal cartilages 1–7; intertubercular sulcus of humerus.

Latissimus Dorsi (action)

Extension, adduction, and medial rotation of the arm.

Latissimus Dorsi (attachment)

T7–L5; ribs 9–12; iliac crest; intertubercular sulcus of humerus.

Supraspinatus (action)

Abduction of the arm.

Infraspinatus (action)

Lateral rotation of the arm.

Teres Minor (action)

Lateral rotation and adduction of the arm.

Subscapularis (action)

Medial rotation of the arm.

Teres Major (action)

Extension, adduction, and medial rotation of the arm.

Brachialis (action)

Flexion of the forearm at elbow joint.

Biceps Brachii (action)

Supination of forearm at radioulnar joint; flexion of the forearm at elbow joint; flexion of the humerus at the shoulder (long head only).

Biceps Brachii (attachment)

Glenoid cavity (long head); coracoid process of scapula (short head); radial tuberosity; fascia of forearm.

Triceps Brachii (action)

Extension of the forearm at elbow (whole group); extension and adduction of the humerus at the shoulder (long head only).

Triceps Brachii (attachment)

Glenoid cavity and joint capsule (long head); posterior surface of head of humerus (lateral head); posterior surface of humeral shaft (medial head); olecranon process of ulna; fascia of forearm.

Anconeus (action)

Extends forearm at elbow.

Brachioradialis (action)

Flexion of the forearm at elbow.

Brachioradialis (attachment)

Lateral supracondylar ridge of humerus; lateral surface of radius near styloid process.

Pronator Teres (action)

Pronation of the forearm at radioulnar joint.

Supinator (action)

Supination of forearm at radioulnar joint.

Flexor Carpi Radialis (action)

Anterior flexion of wrist; radial/lateral flexion (abduction) of wrist.

Flexor Carpi Ulnaris (action)

Anterior flexion of wrist; ulnar/medial flexion (adduction) of wrist.

Palmaris Longus (action)

Anchors skin and fascia of the palm; weak flexor of hand at wrist.

Flexor Digitorum Superficialis (action)

Anterior flexion of wrist; flexion of metacarpophalangeal and middle interphalangeal joints of digits 2–5.

Flexor Pollicis Longus (action)

Flexion of metacarpophalangeal and interphalangeal joints of the thumb; weak flexor of hand at wrist.

Extensor Carpi Radialis Longus and Brevis (action)

Extension of wrist; radial/lateral flexion (abduction) of wrist.

Extensor Digitorum (action)

Extension of metacarpophalangeal and interphalangeal joints of digits 2–5; extension of wrist.

Extensor Carpi Ulnaris (action)

Extension of wrist; ulnar/medial flexion (adduction) of wrist.

Iliopsoas Muscle (action)

Flexion of thigh at hip when trunk is fixed; flexion of trunk when hip is fixed.

Tensor Fasciae Latae (action)

Abduction and medial rotation of thigh at hip.

Gluteus Maximus (action)

Extension and abduction of thigh at hip; elevation of trunk.

Gluteus Maximus (attachment)

Posterior surface of ilium, coccyx, and sacrum; gluteal tuberosity of femur; lateral condyle of tibia via iliotibial tract.

Gluteus Medius (action)

Abduction and medial rotation of thigh at hip.

Adductor Group (Brevis, Longus, Magnus) (action)

Adduction and flexion of thigh at hip.

Adductor Brevis and Longus (attachment)

Body and inferior ramus of pubis; linea aspera of femur.

Adductor Magnus (attachment)

Inferior ramus of pubis; ischial tuberosity and ramus; linea aspera, gluteal tuberosity, and supracondylar line of femur.

Gracilis (action)

Adduction of the leg at the hip; flexion and medial rotation of tibia at knee.

Pectineus (action)

Flexion and adduction of thigh at hip.

Rectus Femoris (action)

Extension of knee; flexion of thigh at hip; flexion of trunk when thigh is fixed.

Rectus Femoris (attachment)

Anterior inferior spine of ilium; superior margin of acetabulum; capsule of hip joint; patella; tibial tuberosity; lateral and medial condyles of tibia via the patellar tendon.

Vastus Lateralis (action)

Extension of knee.

Vastus Lateralis (attachment)

Greater trochanter of femur; gluteal tuberosity and linea aspera of femur; patella; tibial tuberosity; lateral and medial condyles of tibia via the patellar tendon.

Vastus Medialis (action)

Extension of knee.

Vastus Medialis (attachment)

Intertrochanteric line and supracondylar line of femur; linea aspera; patella; tibial tuberosity; lateral and medial condyles of tibia via the patellar tendon.

Vastus Intermedius (action)

Extension of knee.

Sartorius (action)

Flexion and lateral rotation of thigh at hip; flexion of knee.

Biceps Femoris (action)

Extension of thigh at hip; flexion of knee.

Biceps Femoris (attachment)

Ischial tuberosity (long head); linea aspera (short head); head of fibula.

Semitendinosus (action)

Extension of thigh at hip; flexion of knee; medial rotation of tibia at knee when flexed.

Semitendinosus (attachment)

Ischial tuberosity; medial surface of upper tibia; medial condyle of tibia.

Semimembranosus (action)

Flexion of knee; extension of thigh at hip; medial rotation of tibia at knee when flexed.

Semimembranosus (attachment)

Ischial tuberosity; medial condyle of the tibia and lateral condyle of femur; popliteal ligament.

Gastrocnemius (action)

Plantar flexion of foot; flexion of the knee.

Gastrocnemius (attachment)

Condyles and popliteal surface of tibia; calcaneus.

Tibialis Anterior (action)

Dorsiflexion and inversion of the foot.

Soleus (action)

Plantar flexion of foot.