Shoulder Muscles Flashcards
3 Muscles the attach to the Coracoid Process
- Short head of the biceps brachia
- Pec Minor
- Coracobrachialis
Short head of Biceps Brachii
O: Coracoid process
I: Tuberosity of radius/fascia of forearm via bicipital aponeurosis
A: Flexes forearm at elbow, supinates flexed forearm
N: Musculocutaneous C5, 6
Coracobrachialis
O: Coracoid process
I: middle third of medial surface of humerus
A: helps to flex and adduct the shoulder
N: Musculocutaneous C5-7
Pec Minor
O: ribs 3-5
I: coracoid process
A: depresses and protracts the scapula
N: Medial pec nerve C8, T1
What works to provide stability to the shoulder?
Rotator Cuff: Supraspinatus, Infraspinatous, Teres Minor, Subscapularis
What portion of the shoulder joint is the weakest?
Glenoid labrum: cartilage pillow that deepens glenoid cavity cavity by 50% helps for a more secure humeral head in the glenoid fossa.
Glenohumeral joint capsule: allows for more stability during internal and external rotation of the shoulder
The inferior part of the the capsule is the weakest area AND dislocation of humerus into axilla through inferior part of the capsule is common
Quadrangular space
Upper: teres minor
Lower: teres major
Medial: long head of triceps
Lateral: shaft of the humerus
What passes through the Quadrangular space?
Axillary Nerve and posterior circumflex humeral artery
Axillary nerve injuries
Entrapment of Quadrangular space: Loss of motor function of the deltoid and teres minor
Loss of sensory function to the skin over the lateral shoulder, i.e., superior lateral cutaneous nerve of the arm
Acromioclavicular Joint Ligaments
Acromioclavicular: (acromion to clavicle): reinforces the joint
Coracoclavicular (Conoid and trapezoid ligaments) : Reinforces the joint– provides stability: Produces longitudinal rotation of the clavical necessary for full ROM
Coracoacromial: acromion to coracoid process
3 degrees of freedom (AB/ADduction, elevation/depression, upward/downward rotation), allows scapula to move in motion with arm. small movements but important for stability, if ligaments were to tear it would be a shoulder separation
Triangular Space
Upper: Teres Minor
Lateral: Long Head of triceps
Lower: Teres Major
Passes through: circumflex scapular artery
17 Muscles that attach to the scapula
SSS TTTT BRR COLD LIP
+ major deficit that occurs if a given muscle does not function properly
Seratus Anterior
Scapular winging; can no longer hold scapula against thoracic wall
Subscapularis
Rotator cuff injury; ADduction deficit
Supraspinatus
Rotator cuff injury; ABduction and medial rotation deficit
Teres Minor
Rotator cuff; lateral rotation deficit, difficulty holding humeral head in glenoid
Teres Major
ADduction and Medial rotation deficit (of scapula/shoulder joint)
Trapezius
Drooping shoulder (aka “shoulder drop”); scapular elevation deficit
Triceps Long Head
Forearm extension deficit (stabilization)
Biceps
Forearm flexion and supination deficit
Rhomboid Minor
Inability to retract scapula; scapular instability (winging)
Rhomboid Major
Inability to retract scapula; scapular instability (winging)
Corocobrachialis
Inability to to flex/aDduct arm; pinched musculocutaneous n.
Omohyoid Inferior Belly
Problems with swallowing (inability to depress hyoid)
Latissimus Dorsi
Inability to ADduct and extend arm
Deltoid
Deficit in ABduction of arm
Levator Scapulae
inability to elevate scapula
Infraspinatus
Rotator cuff; lateral rotation deficit, difficulty holding humeral head in glenoid
Pec Minor
Chronic Tension = winging of scapula; poor posture, rounded shoulders, etc.
–>A tear may also lead to deficits in protraction and depression of scapula
Deep Forearm: Anterior Compartment
FDP
Pronator Quadrates
FPL
FDP
O: anterior medial ulna
I: distal phalanx of digits 2-5
A: flexes hand at wrist and PIP and DIP of digits 2-5
N: 1/2 ulnar, 1/2 AIN (C8, T1)
Pronator Quadrates
O: distal 1/4 ulna
I: distal 1/4 of radius
A: pronates forearm
N: AIN (C8, T1)
FPL
O: mid radius
I: distal phalanx of thumb
A: flexes thumb at IP
N: AIN (C8, T1)
Deep Forearm: Posterior Compartment
Supinator APL EPB EPL Extensor Indices
Supinator
O: lateral epicondyle
I: proximal radius
A: Supinates the forearm
N: Deep branch of radial
ABductor Policis Longus
O: posterior surfaces of ulna, radius and IM
I: base of 1st MC
A: abducts thumb
N: PIN C7, C8
Extensor Policis Brevis
O: posterior surface of radius and IM
I: proximal phalanx of thumb
A: extend and abducts thumb
N: PIN C7, C8
Extensor Policis Longus
O: posterior surface of ulna and IM
I: Distal phalanx of thumb
A: extends and abducts thumb
N: PIN C7, C8
Extensor Indices
O: posterior surface of ulna and IM
I: Extensor hood of digit 2
A: Extends 2nd digit
Trapezius Nerve Roots
Cranial XI
Rhomboids Maj/Min
C4, C5
Levator Scapulae
C5
Subclavius Teres Minor and Major Deltoid Supraspinatus Infraspinatus Biceps Brachii (L&S) Brachialis Supscapularis
C5, C6
Coracobrachialis, Sertus Anterior, Pec Major (later pec n),
C5,C6, C7
Latissimus Dorsi
C6, C7, C8
Triceps, Anconeous
C6, C7, C8
Pec Minor
C8, T1
SUPERFICIAL ANTERIOR of Forearm (Flexors)
Pronator Teres, FCR, Palmaris Longus, FCU
Pronator Teres/FCR
C6,C7
Palmaris Longus
C7, C8
FCU
Ulnar: C7-T1
Flexor Digitorum Superficialis
Median C8, T1
DEEP ANTERIOR of Forearm (Flexors)
FPL, FDP, Pronator Quadrates
FDP
Medial 1/2 Ulnar
Lateral 1/2 AIN (C8, T1)
FPL, Pronator Quadrates
AIN C8, T1
Superficial Extensor: Brachioradialis
C5,6
ECRL
C6, 7
ECRB & Supinator
DEEP BRANCH of radial C7
Extensor Digitorum, EDM, ECU, ABductor PL, EPB, EPL, Extensor Indices
PIN (C7, C8)
Intrinsic Muscles of the Hand
Are ALL Deep Ulnar C8, T1, EXCEPT: 1st two lumbercles and the thinner eminence
1st & 2nd Lumbercles
Median C8, T1
Thenar Eminence
Motor Recurrent branch of median nerve
Carpal Bones
Scaphoid, Lunate, Triquetrium, Pisiform
Trapezium, Trapazoid, Capatate, Hamate
Clinical Entities of Carpal Bones
Dislocation and Instability
Dislocation
Lunate or Hamate (perilunate)
Instability
Normal Angles: CapitoLunate (CL) = 30 & Scaphoid-Lunate (SL) = 30-60
DISI (dorsal flexion) CL = or > than 30 & SL > 60
VISI (volar flexion) : CL and SL
6 Extensor Retinaculum Compartments
- APL and EPB
- ECRL and ECRB
- EPL
- Extensor Digitorum and Extensor Indices
- Extensor Digiti Minimi
- ECU
Synovial Sheath of Extensor Retinaculum
Reduce friction and provide cushion; can also lead to infection
Retinacular Structure
Holds tendons in place to prevent popping out during extension
Thenar eminence
ABductor Policis Brevis, Flexor Policis Brevis, Opponens Policis
ABductor Policis Brevis
O: Flexor Retinaculum and Tubercles of the Schaphoid & Trapezium
I: base of proximal phalanx of the thumb
A: abduct the thumb
N: Motor Recurrant Branch of Median nerve
Flexor Policis Brevis
O: Flexor Retinaculum and tubercle of trapezium
I: lateral base of phalanx of the thumb
A: flexes proximal phalanx of thumb
N: Motor Recurrant Branch of Median nerve
Opponens Policis
O:Flexor Retinaculum and tubercle of trapezium
I: lateral side of 1st MC bone
A: opposes thumb toward center of palm and medially rotates it.
N: Motor Recurrant Branch of Median nerve
ADductor Pollicis
O: Oblique head: bases of 2nd and 3rd MCs and Capitate
Transverse head: anterior surface of body of 3rd MC
I: medial side of base of proximal phalanx of thumb
A: Adducts thumb toward middle digit
N: Deep Branch of Ulnar nerve
Hypothenar Eminence
ABductor digiti minimi, Flexor Digiti Minimi Brevis, opponens digiti minimi
ABductor digiti minimi
O: Pisiform and tendon of flexor carpi ulnaris
I: Medial side of base of proximal phalanx of 5th digit
A: abducts 5th digit
N: Deep Ulnar Branch C8, T1
Flexor Digiti Minimi Brevis
O: hook of hamate and flexor retinaculum
I: medial side of base of proximal phalanx
A: flexes proximal phalanx of 5th digit
N: deep ulnar branch C8, T1
Opponens Digiti Minimi
O: hook of hamate and flexor retinaculum
I: palmar surface of 5th metacarpal
A: draws 5th MC anteriorly and rotates it which brings it into opposition with thumb
N: deep ulnar branch C8, T1
Lumbricals 1 & 2
O: lateral 2 tendons of FDP
I: Lateral sides of extensor expansions of 2nd and 3rd digits
A: flexes digits at MCP and extends IP joints
N: Median C8, T1
Lumbricals 3 & 4
O: medial 3 tendons of FDP
I: lateral sides of extensor expansions 4th and 5th digits
A: Flexes digits at MCP and extends IP joints
N: Deep ulnar C8, T1
Dorsal Interosei
O: adjacent sides of two metacarpals
I: extensor expansions and bases of proximal phalanges of 2nd-4th digits
A: ABducts digits
N: Deep ulnar C8, T1
Palmar Interosei
O: sides of 2nd, 4th and 5th MC bones
I: extensor expansions of digits and bases of proximal phalanges of 2nd, 4th, and 5th digits
A: ADducts digits
N: Deep ulnar C8, T1
Ape Hand
Lack of ability to abduct and oppose thumb due to paralysis of the thenar muscles (e.g., the median nerve has been compromised or motor recurrent branch)
Claw Hand
Ulnar nerve, deep ulnar is compromised – dorsal interossei, 3&4 lumbercles
Hypertrophy of pronator terres
Median nerve entrapment, loss of motor movement in thumb
Most comment median entrapment occurs in the wrist
Carpal tunnel
