Muscles of the Back (Lectures) PDF

Muscles of the back www.ipka.medicine.edu.eg  ILOs: By the end of the lectures, the student should be able to:  List the muscles of the back.  Locate the site of attachment of the back muscles.  Mention the nerve supply & actions of the back muscles.  Recall...

Muscles of the back www.ipka.medicine.edu.eg  ILOs: By the end of the lectures, the student should be able to:  List the muscles of the back.  Locate the site of attachment of the back muscles.  Mention the nerve supply & actions of the back muscles.  Recall boundaries and contents of lumbar triangle and triangle of auscultation.  Interpret some clinical problem related to lumbar triangle.  Interpret clinical problem related to the nerve supply to trapezius. www.ipka.medicine.edu.eg Key facts All muscles arise from the back of trunk (origin) All are inserted into scapula except latissimus dorsi (humerus) All act on shoulder girdle except latissimus dorsi acts on shoulder joint All are supplied by brachial plexus except trapizus supplied by spinal accessory nerve (cranial nerve) www.ipka.medicine.edu.eg  The first layer The second layer Trapezius levator scapulae Rhomboidus minor Rhomboidus major Latissimus dorsi www.ipka.medicine.edu.eg  Trapezius muscle Occipital part Cervical part Thoracic part www.ipka.medicine.edu.eg  Trapezius : origin Back of head : External occipital protuberance. Medial 1/3 of the superior nuchal line. Back of neck: Ligamentum nuchae. Spine of C7. Back of thorax: All thoracic spines. Supra-spinous ligaments. www.ipka.medicine.edu.eg  Trapezius : insertion Upper fibres : Posterior border of the lateral 1/3 of the clavicle. Middle fibres : Medial border of the acromion & upper lip of the crest of the spine of the scapula. Lower fibres: Tubercle of the crest of the spine of the scapula. www.ipka.medicine.edu.eg Trapezius : nerve supply Spinal accessory: (Motor). C3 & 4: (Proprioception). www.ipka.medicine.edu.eg Spinal nerves Numbers: 31 pairs Arrangement: 8 cervical. 12 thoracic 5 lumbar 5 sacral One coccygeal www.ipka.medicine.edu.eg Trapezius : action Upper fibres :Elevate the scapula. Middle fibres :Retract the scapula. Lower fibres: elevation of the glenoid cavity. www.ipka.medicine.edu.eg  Trapezius Injury of spinal accessory leads to drop shoulder www.ipka.medicine.edu.eg Latissimus dorsi : origin Lower 6 thoracic spines. Thoraco-lumbar fascia. Posterior part of the outer lip of the iliac crest. Lower 4 ribs. Back of inferior angle of scapula. www.ipka.medicine.edu.eg  Latissimus dorsi : insertion Floor of the bicipital groove. Nerve supply Nerve to dorsi (Thoraco-dorsal nerve). Action Extension, adduction and med. Rot Climbing Violent expiration www.ipka.medicine.edu.eg www.ipka.medicine.edu.eg 1.Triangle of auscaltation 2. Lumbar triangle www.ipka.medicine.edu.eg  Latissimus dorsi Relations: Triple relation with Teres major. Triangle of auscultation. Lumbar triangle. www.ipka.medicine.edu.eg  Levator scapulae Origin : Transverse processes of upper 4 cervical vertebrae. Insertion: Back of the medial border of scapula from the superior angle to the root of the spine. Nerve supply:  C3 & C4 N. to Rhomboideus (C5). Action 1. Elevates shouldera girdle 2. Glenoid down 3. Retract scapula www.ipka.medicine.edu.eg www.ipka.medicine.edu.eg  Rhomboideus minor: Origin : Lower part of the ligamentum nuchae. -Spines C7 & T1. Insertion: Back of the medial border of scapula opposite the root of the spine. www.ipka.medicine.edu.eg  Rhomboideus major Origin : Spines of T2, 3, 4 &5. -Supra-spinous ligaments. Insertion: Back of the medial border of scapula from the root of spine to the inferior angle. www.ipka.medicine.edu.eg  Rhomboideus action Nerve supply: Nerve to Rhomboideus (dorsal scapular nerve) C5. Action: Downword rotation of glenoid cavity. With the middle fibres of trapezius: Retraction of the scapula. www.ipka.medicine.edu.eg www.ipka.medicine.edu.eg www.ipka.medicine.edu.eg www.ipka.medicine.edu.eg