Muscles Flashcards
Erector Spinae Group (3) from lateral to medial: iliocostalis, longissimus, spinalis (ILS)
Origin: BROAD tendon which originates at the posterior part of the iliac crest, posterior sacrum, sacro-iliac ligaments, and sacral & lumbar spinous processes (SPs)
Insertion: spinous processes (SPs) in the thoracic and cervical region, angles of ribs and cervical and thoracic transverse processes (TVPs), and longissimus extending up into the mastoid process of the occiput
Actions: bilaterally extends the spine & unilaterally laterally flexes the spine (ipsilateral) - same side
Nerve Innervation: posterior rami of spinal nerves
Sternocleidomastoid
Origin: manubrium of the sternum & medial clavicle
Insertion: mastoid process & lateral half of superior nuchal line
Actions: bilaterally: extends head and neck, flexes the neck, and elevation of sternum & clavicle during forced inhalation + unilaterally laterally flexes head & neck, contralaterally rotates head & neck
Nerve Innervation: spinal accessory Nerve
Scalene Muscle Group ( 3: Anterior, Middle, Posterior)
Origin: transverse processes of C3 - C7
Insertion: anterior & middle insert on 1st rib, posterior inserts on 2nd rib
Actions: all 3- anterior, middle, and posterior flex the neck laterally, anterior & middle elevate the 1st rib during forced inhalation, posterior elevates the 2nd rib during forced inhalation
Nerve Innervation: ventral rami of the cervical spinal nerves c3-c8
Temporalis (mastication)
Origin: temporal fossa and temporal fascia
Insertion: coronoid process & anterior border of the ramus of the mandible
Actions: elevation & retraction of the mandible
Nerve Innervation: mandibular nerve
Masseter (mastication)
Origin: zygomatic arch
Insertion: lateral surface of the ramus of mandible
Action: elevation & protraction of the mandible
Innervation: mandibular nerve
Rectus Abdominus
Origin: pubic crest and symphysis pubis
Insertion: xiphoid process, cartilage of ribs 5,6,7
Action: flexes the trunk at the spinal joints, allows for posterior pelvic tilt (stick butt in), also compresses abdominal contents
Innervation: intercostal nerves T6-T12 (6 pack)
External Abdominal Oblique Muscle
Origin: external surfaces of ribs 5-12
Insertion: linea alba, pubic tubercle, anterior half of iliac crest
Action: Flexes the trunk, contralaterally rotates the trunk, compresses abdominal muscles
Innervation: intercostal nerves T7-T12
Rhomboid Major & Minor
Origin: R Minor is the spinous processes of C7 and T1 & R Major is spinous processes of T2 - T5
Insertion: medial border of scapula at the root of the spine & the medial border of scapula inferior to the spine
Action: (same for both) retracts the scapula, elevates the scapula, and downwardly rotates the scapula
Innervation: dorsal scapular nerve
Trapezius (Traps): Upper, Middle, Lower
Origin: Upper attaches on the external occipital protuberance and medial superior nuchal line & spinous process of C7,
Middle is the SPs of T1 - T5, Lower is SPs of T6 - T12
Insertion: (all three together) lateral ⅓ of clavicle, acromion, spine of scapula
Action: Upper (strongest) extends and laterally flexes the head and neck, contralaterally rotates the head and neck, elevates the scapula, and upwardly rotates scapula. Middle retracts the scapula. Lower (weakest) upwardly rotates scapula and depresses scapula.
Innervation: spinal accessory nerve
Latissimus Dorsi - “swimmers muscle”
Origin: spinous processes of T7 -L5, crests of ilium and sacrum, lowest 4 ribs via the thoracolumbar fascia
Insertion: floor of the intertubercular groove of the humerus (anterior humerus)
Action: extends, adducts, and medially rotates the arm + anterior pelvic tilt
Innervation: thoracodorsal nerve
Pectoralis Major (Pec Major) - 2 HEADS = 2 N
Origin:
Clavicular head (superior fibres): medial half of clavicle
Sternocostal head (inferior fibres): sternum, costal cartilage of ribs 1-7
Insertion: lateral edge of bicipital groove in humerus
Action: flexes, adducts, and medially rotates the arm + horizontally adducts the arm and depresses the shoulder
Nerve: Lateral & Medial Pectoral Nerve
Supraspinatus (first S in SITS)
Origin: supraspinous fossa
Insertion: greater tubercle of humerus
Action: abduction of shoulder joint and stabilizes glenohumeral joint
Innervation: suprascapular nerve
Serratus Anterior
Origin: upper 9 ribs (ribs 1-9)
Insertion: anterior surface of the medial border of scapula
Action: protracts & upwardly rotates the scapula
Innervation: long thoracic nerve
Deltoid
Origin: lateral clavicle, acromion, spine of scapula
Insertion: deltoid tuberosity of humerus
Action: flexes, extends, medially and laterally rotates shoulder joint + abducts shoulder
Innervation: Axillary Nerve
Infraspinatus (I in SITS)
Origin: infraspinous fossa
Insertion: greater tubercle of humerus
Action: laterally rotates shoulder + horizontally abducts shoulder
Innervation: suprascapular n
Teres Minor (T in SITS)
Origin: inferior lateral border of scapula, above teres major
Insertion: greater tubercle of humerus
Action: laterally rotates shoulder
Innervation: axillary nerve
Subscapularis
Origin: subscapular fossa
Insertion: lesser tubercle of humerus
Action: medially rotates the shoulder
Nerve: suprascapular nerve
Teres MAJOR - similar to lats how?
Same actions as lats (swimmers muscle)
Origin: inferior lateral border of scapula (below minor)
Insertion: middle lip of bicipital groove of humerus
Action: extends, adducts, and medially rotation of shoulder joint
Nerve: lower subscapular nerve
Biceps - 2 HEADS
Origin: longhead starts at the supraglenoid tubercle of scapula & short head at coracoid process of scapula
Insertion: radial tuberosity & the fascia of forearm via the bicipital aponeurosis
Action: flexes and supinates the forearm + weakly flexes the shoulder via longhead ONLY!
Innervation: musculocutaneous nerve
Triceps - 3 heads
Origin: in order from outside to inside - lateral, long, medial
Lateral head begins on lateral, posterior surface of humerus.
Longhead on the infraglenoid process of the scapula & infraglenoid tubercle of scapula.
Medial head on the posterior surface of humerus
Insertion: Olecranon process of the ulna
Action: extends elbow + long head only will extend and hyperextend the shoulder
Innervation: radial nerve
Pronator Teres
Origin: medial epicondyle via common flexor tendon + coronoid process of ulna
Insertion: middle of the lateral surface of the radius
Action: pronates & weakly flexes forearm
Innervation: Median nerve
Flexor Carpi Radialis
Origin: medial epicondyle via common flexor tendon
Insertion: base of 2nd and 3rd metacarpals
Action: flexes the wrist, abducts (radially deviates) the wrist, & weakly flexes the elbow
Innervation: Median nerve
Flexor Carpi Ulnaris - 2 HEADS
Origin: humeral head at the medial epicondyle of humerus via common flexor tendon, ulnar head at the olecranon process & posterior border of ulna
Insertion: Base of 5th metacarpal, hook of hamate, pisiform
Action: Flexes & adducts (ulnar deviation) the wrist
Innervation: Ulnar N.
Flexor Digitorum Superficialis - 2 HEADS
Origin: humero-ulnar head at the medial epicondyle and coronoid process of ulna, radial head starts at the proximal, anterior border of radius
Insertion: base of middle phalanges of fingers 2-5
Action: flexes fingers 2-5 (all but thumb) @ MCP and PIP joints, flexes the wrist, and weakly flexes the elbow
Innervation: Median nerve
Extensor Carpi Radialis Longus
Origin: distal 1/3 of lateral supracondylar ridge of humerus
Insertion: base of 2nd metacarpal
Action: extends and abducts (radial deviation) the wrist + weakly flexes the elbow
Innervation: radial nerve
Brachioradialis - beer drinking muscle
Origin: proximal 2/3 of the lateral supracondylar ridge of humerus
Insertion: lateral surface of the distal end of radius, proximal to styloid process
Action: flexes the elbow in mid pronation (beer drinker)
Innervation: radial nerve
Extensor Digitorum (MCP, PIP, DIP)
Origin: lateral epicondyle of humerus via common extensor tendon
Insertion: distal and middle phalanges of fingers #2 – 5 via the dorsal digital expansion (DDE)
Action: extends fingers 2-5 at MCP, PIP, and DIP joints + extends the wrist
Innervation: radial nerve
Abductor Pollicis Longus
Origin: the middle, posterior surface of radius, ulna, and interosseous membrane
Insertion: base of the 1st metacarpal (thumb)
Action: abducts & extends the thumb at CMC joint + weakly abducts (radial deviation) the wrist
Innervation: radial nerve
Abductor Pollicis Brevis
Origin: flexor retinaculum, tubercle of scaphoid, tubercle of trapezium
Insertion: lateral side of the base of proximal phalanx of thumb
Action: abducts thumb
Innervation: median nerve
Flexor Pollicis Brevis
Origin: Flexor retinaculum & trapezium
Insertion: lateral side of the base of proximal phalanx of thumb
Action: flexes thumb
Innervation: median nerve
Dorsal Interossei (DAB)
Origin: adjacent sides of metacarpals
Insertion: base of proximal phalanges and dorsal digital expansion of fingers (#2, #3, and #4)
Dorsal interosseous #1 to the lateral side of the index finger
Dorsal interosseous # 2 to the lateral side of the middle finger
Dorsal interosseous # 3 to the medial side of the middle finger
Dorsal interosseous # 4 to the medial side of the ring finger
Action: abducts fingers 2,3,4 @ MCP joints, TATA fingers 2,3,4
Innervation: ulnar nerve
Tensor Fascia Lata
Origin: lateral side of ASIS, anterior part of the iliac crest
Insertion: Tibia (gerdy’s tubercle) via the IT band (which starts ⅓ way down the thigh)
Action: flexes the hip & knee, abducts and medially rotates the hip, anterior pelvic tilt, and tenses the IT band to provide support while standing
Innervation: superior gluteal nerve
Sartorious - S of SGT
Origin: ASIS
Insertion: proximal medial shaft of tibia (pes anserine)
Action: flexes the hip and knee, laterally rotates the hip joint, and abducts the hip
Innervation: femoral nerve
Biceps Femoris (hamstring) 2 HEADS
Origin: Long head begins at ischial tuberosity (sit bone) and short head at the linea Aspera of femur on posterior side
Insertion: head of fibula, lateral condyle of tibia
Action:
extends and externally rotates the hip + flexes and externally rotates the knee, also stabilizes the pelvis
Innervation: tibial branch and common fibular branches of the sciatic nerve
Semitendinosus
Origin: ischial tuberosity
Insertion: proximal medial shaft of tibia
Action: flexes and medially rotates the knee + extends the hip
Innervation: tibial branch of sciatic
Rectus Femoris (2 HEADS)
Origin: straight head begins at AIIS, the reflected head at the acetabulum
Insertion: quadriceps tendon to the patellar ligament onto tibial tuberosity
Action: flexes hip, extends the knee
Innervation: femoral nerve
Vastus Medialis
Origin: intertrochanteric line, medial lip of linea aspera, medial supracondylar line
Insertion: quadriceps tendon to the patellar ligament onto tibial tuberosity (same insertion as Rectus Femoris)
Action: extends the knee
Innervation: femoral nerve
Adductor Muscles as a group (longus, brevis, magnus, pectineus and gracilis)
Origin: pubis and ischium
Insertion: pectineal line of femur (pectineus), linea aspera of femur (longus, brevis, magnus) down to the tibia (gracilis)
Action: flexes, laterally rotates, and adducts the hip, and gracilis flexes the knee
Innervation: obturator nerve and femoral nerve for pectineus muscle
Gastrocnemius
Origin: medial and lateral condyles of femur
Insertion: achilles tendon
Action: plantar flexion
Innervation: tibial nerve
