back and upper limb

Back and upper limb

General division of the back

musclesSuperficial extrinsic back muscles

(posterior thoracoappendicular muscles)

Intermediate extrinsic back muscles

(spinocostal muscles)

Extrinsic back muscles

Superficial layer

(Splenius muscles)

Intermediate layer

(Erector spinae)

Deep layer

(Transverospinal muscles)

Minor deep layer

(Short back muscles)

Intrinsic back muscles

Back muscles

Superficial extrinsic back muscles (posterior thoracoappendicular or extrinsic shoulder muscles)

Superficial posterior thoracoappendicular muscles

Trapezius

Latissimus dorsi

Deep posterior thoracoappendicular muscles Levator scapulae

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


Trapezius

Innervation

Spinal roots of

accessory nerve

(CN XI)

Cervical plexus


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


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


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


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

Latissimus dorsi

Raising the body


Levator scapulae

Attachments

Origin

• Transverse

processes of C1 to

C4 vertebrae

Insertion

• Superior part of

medial border of

scapula


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


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


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

Intrinsic (deep) back muscles

Innervation- dorsal rami of the

spinal nerves

Superficial extrinsic back muscles

(posterior thoracoappendicular muscles)

Intermediate extrinsic back muscles

(spinocostal muscles)

Extrinsic back muscles

Superficial layer

(Splenius muscles)

Intermediate layer

(Erector spinae)

Deep layer

(Transverospinal muscles)

Minor deep layer

(Short back muscles)

Intrinsic back muscles

Back muscles

Intrinsic (deep) back musclesAction

•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

Erector spinaeErector spinae

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 triangleBoundaries

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 anddepression 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

Erector spinaeSerratus anterior

Pushing a wall

Scapulohumeral (intrinsic shoulder) muscles

Deltoid muscle

Rotator cuff muscles

Supraspinatus

Infraspinatus

Teres minor

Subscapularis

Teres major muscle


Deltoid muscle

Attachments

Proximal

• Posterior part: spine of

scapula

• Middle part- acromion

• Anterior part- clavicle

Distal

Deltoid tuberosity of humerus

Innervation

Axillary nerve (branch of the

posterior cord of brachial

plexus)


Deltoid muscle

Main action

Posterior part:

extension and lateral

rotation of arm

Middle part-

abduction of arm

(cooperates with

supraspinatus)

Anterior part-

flexion and medial

rotation of arm

Scapulohumeral (intrinsic shoulder) musclesMuscles of rotator cuff

Rotator cuff muscles form a

musculotendinous cuff around

the glenohumeral joint

Rotator cuff muscles reinforce

and stabilize the glenohumeral

joint blending with its articular

capsule

Supraspinatus muscle

Infraspinatus muscle

Teres minor

Subscapularis muscle



Attachments

Proximal

• Supraspinous fossa of scapula

Distal

• Superior facet on greater tubercle of humerus

Innervation

Suprascapular nerve(branch of the superior trunk of brachial plexus)

Action

Abduction of arm

Between the acromion and the tendon of

supraspinatus is located the subacromial bursa.

Subacromial bursa, filled with synovial fluid, diminish

friction of supraspinatus during its contraction.



Attachments

Proximal

• Infraspinous fossaof scapula

Distal

• Middle facet on greater tubercle of humerus

Innervation

Suprascapular nerve (branch of the superior trunk of brachial plexus)


Teres minor

Attachments

Proximal

• Lateral border of scapula

Distal

• Inferior facet on greater tubercle of humerus

Innervation

Axillary nerve (branch of the posterior cord of

brachial plexus)

Action of

infraspinatus and teres minor

Lateral rotation of arm



Attachments

Proximal

• Subscapular fossa of scapula

Distal

• Lesser tubercle of humerus

Innervation

Subscapular nerves (branches of

the posterior cord of brachial

plexus)

Action

Medial rotation of arm

Tearing of the rotator cuff tendons


Teres major

Attachments

Proximal

• Inferior angle of scapula

Distal

• Medial lip of intertubercular groove of humerus

Innervation

Subscapular nerves(branches of the posterior cord of brachial plexus)

Action

Adduction and medial rotation of arm

Axilla (armpit)

Axilla (armpit)

Pyramidal space between

thorax and upper limb

Axilla provides a

passageway from neck for

vessels and nerves supplying

upper limb

Boundaries of axilla

Apex- entrance from neck

Situated between 1st rib, clavicle and

subscapularis

Base of axilla

Skin, subcutaneous tissue and axillary

fascia

Boundaries of axilla

Anterior wall- formed by pectoralis

major and pectoralis minor muscles

Posterior wall- formed by scapula

and subscapularis muscle and

latissimus dorsi and teres major

muscles

Medial wall- formed by wall of

thorax and covering it serratus

anterior

Lateral wall (or narrow lateral

border)- formed by intertubercular

groove of humerus

Contents of axilla

Brachial plexus (its cords

and branches)

Axillary blood vessels

Axillary artery and its

branches

Axillary vein and its

tributaries

Axillary lymph nodes

Openings in the posterior wall of axilla

Quadrangular space

Boundaries

Superior- teres minor

Inferior- teres major

Medial- long head of triceps brachii muscle

Lateral- surgical neck of humerus

Contents

Axillary nerve

Posterior circumflex humeral artery

Openings in the posterior wall of axilla

Triangular space

Boundaries

Superior- teres minor

Inferior- teres major

Lateral- long head of triceps brachii muscle

Contents

Circumflex scapular artery

Brachial plexus

Location of the brachial plexus

Supraclavicular partSupraclavicular

region of the neck between the anterior and middle scalene muscles

Infraclavicular partAxilla

Brachial plexus (supraclavicular part)

Roots of the brachial

plexus

Ventral rami of last four

cervical spinal nerves and

first thoracic nerve

(C5 to T1 nerves)

Situated in the neck

(posterior triangle) between

anterior and middle scalene

muscles

Brachial plexus (supraclavicular part)Trunks of the brachial

plexus

In the inferior part of the neck (posterior triangle), between the anterior and middle scalene muscles, roots of the brachial plexus unite to form the trunks of the brachial plexus

Superior trunk (union of C5 and C6 roots)

Middle trunk (continuation of C7 root)

Inferior trunk (union of C8 and T1 roots)

Brachial plexus (infraclavicular part)

Cords of the brachial plexus

In the place of passage between

clavicle and 1st rib

(cervicoaxillary canal) each

trunk of the brachial plexus

divides into anterior and

posterior divisions

Divisions of the brachial plexus

form three cords located in axilla

Posterior cord (posterior

divisions of all three trunks)

Lateral cord (anterior

divisions of superior and

middle trunks)

Medial cord (anterior

division of inferior trunk)

Interscalene block of the brachial plexus

Supraclavicular block of the brachial plexus

Infraclavicular block of the brachial plexus

Axillary block of the brachial plexus

Supraclavicular nerves of brachial plexus

Dorsal scapular nerve

Arises from C4 and

C5 roots

Runs along medial

border of scapula

Innervates

Levator scapulae

Rhomboid minor

Rhomboid major


Long thoracic nerve

Arises from C5, C6 and C7

roots

Runs on the lateral wall of

thorax, on the surface of

serratus anterior muscle

Innervates

Serratus anterior muscle

Symptoms of injury

Winged scapula


Suprascapular nerve

Arises from superior trunk of the

brachial plexus

Passes across the posterior

triangle of the neck, and via the

scapular notch reaches the

supraspinous fossa of scapula

Innervates



Symptoms of injury

Difficulties with abduction of arm

Supraclavicular nerves of brachial plexusNerve to subclavius

Arises from superior trunk of the brachial plexus

Runs posteriorly to clavicle

Innervates

Subclavius muscle

Short (side) nerves of the infraclavicular part of brachial plexus

Lateral (from lateral

cord) and medial (from

medial cord) pectoral

nerves

Pierce the clavipectoral

fascia and reach deep

surfaces of the

pectoralis major and

minor muscles


Subscapular nerves (upper

and lower) from posterior

cord of the brachial plexus

Pass posteriorly and

inferolaterally

Innervate


Teres major muscle


Thoracodorsal nerve

from posterior cord

of the brachial

plexus

Runs inferolaterally

along the posterior

axillary wall to

latissimus dorsi

Innervate

Latissimus dorsi

muscle

Short nerves of the infraclavicular part of brachial plexus

Axillary nerve from posterior cord of the

brachial plexus

Leaves the axilla via the quadrangular space, winds around the surgical neck of humerus, reaches deltoid and teres minor, gives rise to lateral brachial cutaneous nerve

Innervate

Deltoid muscle

Teres minor muscle

Shoulder joint

Skin over inferior part of deltoid

Injury

May be caused by fracture of the surgical neck of humerus or dislocation of the head of humerus from the shoulder joint

Symptoms

Difficulties with abduction of shoulder joint

Area of anesthesia on the lateral surface of the shoulder

Palsy of axillary nerve

Atrophy of deltoid

muscle

Long nerves of the infraclavicular part of brachial plexus

Posterior cord

Radial nerve

Lateral cord

Musculocutaneous nerve

Lateral root of the median nerve

Medial cord

Ulnar nerve

Medial root of the median nerve

Medial brachial cutaneous nerve

Medial antebrachial cutaneous nerve

back and upper limb

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