Back and upper limb Back muscles General division Extrinsic back muscles of the back muscles Superficial extrinsic back muscles (posterior thoracoappendicular muscles) Intermediate extrinsic back muscles (spinocostal muscles) Intrinsic back muscles Superficial layer (Splenius muscles) Intermediate layer (Erector spinae) Deep layer (Transverospinal muscles) Minor deep layer (Short back muscles) Superficial extrinsic back muscles (posterior thoracoappendicular or extrinsic shoulder muscles) Superficial posterior Deep posterior thoracoappendicular thoracoappendicular muscles muscles Levator scapulae Trapezius Latissimus dorsi Rhomboid minor Rhomboid major Superficial extrinsic back muscles (posterior thoracoappendicular or extrinsic shoulder muscles) Trapezius Attachments Origin (proximal attachment) • Occipital bone, nuchal ligament and spinous processes of C7 to T12 vertebrae Insertion (distal attachment) • Clavicle, acromion and spine of scapula Superficial extrinsic back muscles (posterior thoracoappendicular or extrinsic shoulder muscles) Trapezius Innervation Spinal roots of accessory nerve (CN XI) Cervical plexus Superficial extrinsic back muscles (posterior thoracoappendicular or extrinsic shoulder muscles) Trapezius Function- movements of scapula: Superior part- elevation Middle part- retraction Inferior part- depression Common action of superior and inferior parts results in rotation of scapula which enables elevation of the arm above the level of the shoulder. Trapezius cooperates then with serratus anterior muscle Superficial extrinsic back muscles (posterior thoracoappendicular or extrinsic shoulder muscles) Latissimus dorsi Attachments Origin • Spinous processes of T6- T12 vertebrae, thoracolumbar fascia, iliac crest, inferior 3 or 4 ribs Insertion • Floor of the intertubercular groove of humerus Superficial extrinsic back muscles (posterior thoracoappendicular or extrinsic shoulder muscles) Latissimus dorsi Innervation Thoracodorsal nerve- branch of the brachial plexus Thoracodorsal nerve is situated on the posterior wall of the axilla and may be injured during surgery in this region Superficial extrinsic back muscles (posterior thoracoappendicular or extrinsic shoulder muscles) Functions of latissimus dorsi Action on the glenohumeral joint: Extension, adduction and medial rotation (folding arms behind the back) Together with pectoralis major Depresses elevated upper limb (for example during chopping wood) Raises body towards arms during climbing Raising the body Latissimus dorsi Superficial extrinsic back muscles (posterior thoracoappendicular or extrinsic shoulder muscles) Levator scapulae Attachments Origin • Transverse processes of C1 to C4 vertebrae Insertion • Superior part of medial border of scapula Superficial extrinsic back muscles (posterior thoracoappendicular or extrinsic shoulder muscles) Rhomboid minor Attachments Proximal • Nuchal ligament and spinous processes of C7 and T1 vertebrae Rhomboid major Attachments Proximal • Spinous processes of T2 to T4 vertebrae Distal attachments of both rhomboids Medial border of scapula Superficial extrinsic back muscles (posterior thoracoappendicular or extrinsic shoulder muscles) Levator scapulae and rhomboids Function- movements of scapula: Elevation of scapula and tilting the glenoid cavity inferiorly by rotating the scapula Retraction of scapula (rhomboids) Fixing scapula to the thoracic wall Superficial extrinsic back muscles (posterior thoracoappendicular or extrinsic shoulder muscles) Levator scapulae and rhomboids Innervation Dorsal scapular nerve- branch of the brachial plexus (its supraclavicular part- root C4- C5) Testing the rhomboids or dorsal scapular nerve or C4- C5 roots Patient has its hands on the hips and pushes elbows posteriorly against the resistence provided by examiner Intermediate extrinsic back muscles (spinocostal muscles) Serratus posterior superior Attachments Superior- nuchal ligament, spinous processes of C7 to T3 vertebrae Inferior- 2nd to 4th ribs Serratus posterior inferior Attachments Superior- spinous processes of T11 to L2 vertebrae Inferior- 8th to 12th ribs Function of serratus posterior muscles accessory muscles of inspiration Innervation of serratus posterior muscles intercostal nerves Back muscles Intrinsic (deep) back muscles Extrinsic back muscles Innervation- dorsal rami of the Superficial extrinsic back muscles spinal nerves (posterior thoracoappendicular muscles) Intermediate extrinsic back muscles (spinocostal muscles) Intrinsic back muscles Superficial layer (Splenius muscles) Intermediate layer (Erector spinae) Deep layer (Transverospinal muscles) Minor deep layer (Short back muscles) Intrinsic (deep) back muscles Action •Acting bilaterally (together)- extend trunk and head •Acting unilaterally (alone)- flex laterally and rotate trunk and head Superficial layer of the intrinsic back muscles Splenius capitis Splenius cervicis Location Lateral and posterior side of neck Extended between midline and cervical vertebrae (transverse processes- splenius cervicis) and skull (mastoid process of temporal bone- splenius capitis) Main action Acting alone- bend and rotate head to side of active muscle Acting together- extend head and neck ErectorErector spinaespinae Intermediate layer of the intrinsic back muscles (erector spinae) Erector spinae (sacrospinalis) muscle Origin Posterior part of iliac crest and sacrum Parts: Lateral column • Iliocostalis (lumborum, thoracis and cervicis)- attached to the angles of ribs and cervical transverse processes Intermediate column • Longissimus (thoracis, cervicis and capitis)- attached to ribs between angles and tubercules, cervical transverse processes and mastoid process of skull Medial column • Spinalis (thoracis, cervicis and capitis)- attached to spinous processes of thoracic vertebrae and skull Deep layer of the intrinsic back muscles (transversospinal muscles) Transversospinal muscles Attachments Extended between transverse and spinous processes of vertebrae Parts (have different length): Semispinalis (thoracis, cervicis and capitis)- spanns 4-6 segments Multifidi- spann 2- 4 segments Rotatores muscles- spann 1-2 segments Minor deep layer of the intrinsic back muscles Interspinales muscles Intertransversarii muscles Attachments • Extended between spinous or transverse processes of adjacent vertebrae Levatores costarum muscles Extended between transverse processes of thoracic vertebrae and rib situated inferolaterally Suboccipital region Situated in the upper part of the posterior surface of the neck, below the occipital bone, at the level of C1 and C2 vertebrae Covered by the trapezius, splenius capitis and semispinalis capitis muscles Suboccipital muscles (deep neck muscles) Rectus capitis posterior minor Rectus capitis posterior major Rectus capitis lateralis Superior oblique of the head Inferior oblique of the head Suboccipital muscles are extended between C1 or C2 vertebrae and occipital bone. The only exception is the inferior oblique of the head extended between C1 and C2 vertebrae Suboccipital muscles (deep neck muscles) Rectus capitis posterior minor Rectus capitis posterior major Rectus capitis lateral Superior oblique of the head Inferior oblique of the head Suboccipital muscles are innervated by the suboccipital nerve (motor nerve being the posterior ramus of C1 spinal nerve) Suboccipital triangle Boundaries Superomedial- rectus capitis posterior major Superolateral- superior oblique of head Inferolateral- inferior oblique of head Floor- posterior atlanto- occipital membrane, arch of C1 Roof- semispinalis capitis muscle Contents: Suboccipital nerve Vertebral artery Innervation of the skin in the occipital region In the innervation of the skin in the occipital region participate: Greater occipital nerve- posterior branch of the 2nd cervical spinal nerve (C2) Lesser occipital nerve- branch of the cervical plexus (contains the anterior branch of the 3rd cervical spinal nerve C3) 1st cervical spinal nerve C1 (and suboccipital nerve) has no sensory fibers and it results in lack of the C1 dermatome of the skin Greater occipital nerve Exits the vertebral canal between the vertebrae C1 i C2 Runs superiorly under the trapezius and splenius capitis muscles Pierces lateral border of the aponeurosis of the trapezius, just under the inferior nuchal line of the occipital bone In the occipital region runs together with occipital artery Lesser occipital nerve Is a branch of the cervical plexus Arises in the midpoint of the posterior edge of the sternocleidomastoid muscle Blocks of the lesser and greater occipital nerves Block of the sensory branches of the cervical plexus Superficial muscles of the thorax (anterior thoracoappendicular muscles) Pectoralis major Extended between clavicle, sternum and ribs and lateral lip of the intertubercular groove of humerus Main action- adduction, medial rotation and flexion of humerus, muscle of climbing Innervation- medial and lateral pectoral nerves Pectoralis minor Extended between ribs and coracoid process of scapula Main action- protraction and depression of scapula Innervation- medial pectoral nerve Boxer’s muscle Serratus anterior Superficial muscles of the thorax (anterior thoracoappendicular muscles) Serratus anterior Extended between ribs and medial border of scapula Innervation- long thoracic nerve Main action- protraction and rotation of scapula, participation in elevation of arm above the level of shoulder Pushing a wall SerratusErectoranteriorspinae