Lecture 1-Superficial Back & Scapular Region Flashcards
Sternoclavicular Joint
-Manubrium of sternum to clavicle
-connects upper limb to axial skeleton
-Synovial joint w an Articular Disc (helps prevent bones from hitting/grinding)
Ligaments: -Interclavicular ligament -Anterior and Posterior sternoclavicular ligaments -Costoclavicular ligament
Motions: -Predominantly in anetroposterior and vertical planes -Some rotation
Muscles: -NO muscles cross this joint
Acromioclavicular joint
-Acromion process of scapula to clavicle
-connects upper limb to axial skeleton
-Synovial joint
-Stability of AC joint is function of coracoclavicular ligaments
Ligaments: -Acromioclavicular ligament -Coracoclavicular ligament (made of trapezoid and conoid ligaments)
Motions: -Anteroposterior and vertical planes -Some slight axial rotation
Glenohumeral joint
- Glenoid cavity (fossa) of scapula to head of humerus
- connects upper limb to axial skeleton
- Articulation of humeral head to glenoid cavity
- Glenoid cavity “deepend” by glenoid labrum (fibrocartilage), prevents bones from grinding
- Provides stability
Upper Limb Attachment to Axial Skeleton
- Sternoclavicular joint
- Acromioclavicular joint
- Glenohumeral joint
- Thoracoscapular joint
Shoulder Separation
- Disclocation of AC joint, usually from fall/sharp blow to top of shoulder
- AC joint is weak bc has lots of mobility
- After separation, weight of arm dsiplaces clavicle from acromion
Shoulder Dislocations
- GH joint most susceptible to dislocations in abduction and external rotation
- Once out of glenoid cavity, pec major pulls humerus anterosupiorly, axial nerve may be damaged
Thoraco-scapular Joint
-Superfical back muscles allow scapula to move in: -elevation/depression -protraction/retraction -upward/downward rotation
Snapping Scapula
- aka scapulathoracic bursitis/crepitus
- caused by bony alteration or inflamed soft tissue
- painful or painless
- chronic (microtrauma) or acute (macrotrauma)
- often from overuse, worse w overhead movement
Trapezius
-Superficial back
Originates: occipital bone, nuchal ligament, and thoracic spinous processes
Inserts: lateral clavicle, acromion, and spine of scapula,
Innervated by: Accessory Nerve (CN XI)
Action: -Descending (superior) part contraction= elevation of scapula
-Ascending (inferior) part contraction = depression
- Middle part contraction = retraction
-All three part contraction = strong retraction
Latissimus dorsi
-Superficial Back
Originates: Thoracolumbar fascia
Inserts: Intertubercular groove of humerus (anterior part)
Innervated by : Thoracodorsal nerve
Action: Contraction will adduct humerus, slight inner rotation
Levator Scapulae
-Superficial Back
-located above scapula
Originates: Transverse processes of Cv 1-4
Inserts: medial border of scapula above spine
Innervated by: Dorsal Scapular Nerve
Action: Elevates scapula
Rhomboideus Minor and Major
-Superficial Back
Originates: lower nuchal ligament and Cv7-Tv1 (r. minor) or Tv2-5 (r. major)
Inserts: medial border of scapula
Innervated by: Dorsal Scapular Nerve (C5)
Action: -R. minor will elevate
-R. major will retract
Intermediate Back Muscles
- Respiratory in function
- Serratus muscles dont touch scapula, attach ribs to spine
- All Innervated by segmental ventral/anterior rami of spinal nerves
Serratus Posterior Superior
-Intermediate Back Muscle Originates: Nuchal ligament and Tv1-3 Inserts: Ribs 2-5 Innervated by: segmental ventral/anterior rami of spinal nerves Action: Elevates upper ribs
Serratus Posterior Inferior
-Intermediate Back Muscle Originates: Tv11-L2 Inserts: Ribs 9-12 Innervated by: segmental ventral/anterior rami of spinal nerves Action: Depresses lower ribs
Serratus Anterior
-Intermediate Back Muscle
Originates: Ribs 1-9
Inserts: Medial border of scapula (costal surface)
Innervated by: long thoracic nerve (is very superficial)
Action: -protraction and rotation of scapula -keeps medial border and inferior angle of scapula opposed to thoracic wall
Winged Scapula
- Injury to long thoracic nerve
- Serratus anterior cannot contract, scapula pulls away from thorax when pushing against wall
- No abduction past horizontal bc serratus ant. helps rotate scapula upward)
Movements of Scapula
Elevation: -Superficial fibers of trapezius -Levator scapula -Rhomboid minor -Rhomboid major
Depression: Anterior: -pec. minor -serratus anterior (inferior part) Posterior: -Trap (inferior part) -serratus anterior (inferior part)
Protraction: -Pec minor -Serratus anterior
Retraction: -Trap (middle part)
-Rhom. minor -Rhom. major
-Lat. dorsi (doesnt touch scapula, but can pull back humerus)
-Superior rotation: -Trap (superior part, pulls acromion toward neck) -Trap (inferior part, pulls medial part of scapula down) -Serratus anterior (inferior part, pulls scapula down/outward)
Inferior rotation: Anterior: - Pec. minor Posterior: -levetator scaopulae -Rhom. major -Rhom minor -Lat. dorsi
