Thorax
- A
surface anatomy, from the front
- B
- C
axial skeleton, from the front (vertebral column and thoracic cage)
- 1
Acromion
- 2
Clavicle
- 3
Costal margin
- 4
Deltopectoral groove
- 5
Manubrium
- 6
Rib
- 7
Second rib
- 8
Sternal body
- 9
Suprasternal jugular notch
- 10
Thoracic vertebra, body
- 11
Thoracic vertebra, spinous process
- 12
Twelfth rib
- 13
Trapezius
- 14
Xiphoid process
Left first rib (inner) and second rib (outer)
- A
from above
- B
from below
- A
- 1
Angle of rib
- 2
Costal groove
- 3
Groove for subclavian artery and first thoracic ventral ramus
- 4
Groove for subclavian vein
- 5
Head
- 6
Neck
- 7
Scalene tubercle
- 8
Serratus anterior tuberosity
- 9
Shaft
- 10
Tubercle
The atypical ribs are the first, second, tenth, eleventh and twelfth.
The first rib has a head with one facet (A5), a prominent tubercle (A10), no angle and no costal groove. The shaft has superior and inferior surfaces.
The second rib has a head with two facets (B5), an angle (B1) near the tubercle (B10), a broad costal groove (B2) posteriorly, and an external surface facing upwards and outwards with the inner surface facing correspondingly downwards and inwards.
The twelfth rib has a head with one facet (F12) but there is no tubercle, no angle and no costal groove. The shaft tapers at its end (the ends of all other ribs widen slightly).
Ribs and relationships
- C
a typical rib and vertebra articulated, from above
- D
the left fifth rib from behind (a typical upper rib)
- E
the left seventh rib from behind (a typical lower rib)
- F
the left twelfth rib from the front, with attachments
- G
the left twelfth rib from behind, with attachments
- C
- 1
Angle of rib
- 2
Area covered by pleura
- 3
Articular facet of head
- 4
Articular facet of transverse process
- 5
Articular part of tubercle
- 6
Costal groove
- 7
Costotransverse ligament
- 8
Diaphragm
- 9
Erector spinae
- 10
External intercostal
- 11
External oblique
- 12
Head
- 13
Internal intercostal
- 14
Latissimus dorsi
- 15
Levator costae
- 16
Line of pleural reflexion
- 17
Neck of rib
- 18
Non-articular part of tubercle
- 19
Quadratus lumborum
- 20
Shaft of rib
- 21
Serratus posterior inferior
- 22
Tubercle
- 23
Upper costal facet of head of rib
- 24
Upper costal facet of vertebral body
Blue lines, epiphysial lines; green lines, capsule attachments of costovertebral joints
- 1
Area covered by pleura
- 2
Costoclavicular ligament
- 3
Intercostal muscles and membranes
- 4
Lateral costotransverse ligament
- 5
Levator costae
- 6
Scalenus anterior
- 7
Scalenus medius
- 8
Scalenus posterior
- 9
Serratus anterior
- 10
Serratus posterior superior
- 11
Subclavius
- 12
Superior costotransverse ligament
- 13
Suprapleural membrane
The sternum
- A
from the front
- B
from behind
- C
from the right
- 1
Body
- 2
Clavicular notch
- 3
Jugular notch
- 4
Manubrium
- 5
Notch for fifth costal cartilage
- 6
Notch for first costal cartilage
- 7
Notch for fourth costal cartilage
- 8
Notch for sixth costal cartilage
- 9
Notch for third costal cartilage
- 10
Notches for second costal cartilage
- 11
Notches for seventh costal cartilage
- 12
Sternal angle and manubriosternal joint
- 13
Xiphisternal joint
- 14
Xiphoid process
The sternum consists of the manubrium (4), body (1) and xiphoid process (14).
The body of the sternum (1) is formed by the fusion of four sternebrae, the sites of the fusion sometimes being indicated by three slight transverse ridges.
The manubrium (4) and body (1) are bony. The xiphoid process (14) is a cartilaginous structure which frequently shows some degree of ossification. It varies considerably in size and shape.
The manubriosternal and xiphisternal joints (12 and 13) are both symphyses, the surfaces being covered by hyaline cartilage and united by a fibrocartilaginous disc.
The sternum
- 1
Area covered by left pleura
- 2
Area covered by right pleura
- 3
Area in contact with pericardium
- 4
Diaphragm
- 5
Pectoralis major
- 6
Rectus abdominis
- 7
Sternocleidomastoid
- 8
Sternohyoid
- 9
Sternothyroid
- 10
Transversus thoracis
The two pleural sacs are in contact from the levels of the second to fourth costal cartilages (E2 and 1).
F
Thoracic inlet
in an articulated skeleton, from above and in front
The thoracic inlet or outlet (upper aperture of the thorax) is approximately the same size and shape as the outline of the kidney, and is bounded by the first thoracic vertebra (6), first ribs (15), and costal cartilages (3) and the upper border of the manubrium of the sternum (jugular notch, 8). It does not lie in a horizontal plane but slopes downwards and forwards.
The second costal cartilage (12) joins the manubrium and body of the sternum (10 and 1) at the level of the manubriosternal joint (9). This is an important landmark, since the joint line is palpable as a ridge at the slight angle between the manubrium and body, and the second costal cartilage and rib can be identified lateral to it. Other ribs can be identified by counting down from the second.
- 1
Body of sternum
- 2
Costochondral joint (2nd)
- 3
First costal cartilage
- 4
First costochondral joint
- 5
First sternocostal joint
- 6
First thoracic vertebra
- 7
Head of first rib
- 8
Jugular notch
- 9
Manubriosternal joint (angle of Louis)
- 10
Manubrium of sternum
- 11
Neck of first rib
- 12
Second costal cartilage
- 13
Second rib
- 14
Second sternocostal joint
- 15
Shaft of first rib
- 16
Sternal end of clavicle
- 17
Sternoclavicular joint
Heart, left parietal pleura and lung
surface markings, in the female
Brown line, heart; purple line, pleura; green line, axillary tail of breast
The positions of the four heart valves are indicated by coloured ellipses, and the sites where the sounds of the corresponding valves are best heard with the stethoscope are shown.
The manubriosternal joint (10) is palpable and a guide to identifying the second costal cartilage (15) which joins the sternum at this level (see page 183 , F9, 14 and 12).
The pleura and lung extend into the neck for 2.5 cm above the medial third of the clavicle.
In the midclavicular line the lower limit of the pleura reaches the eighth costal cartilage, in the midaxillary line it reaches the tenth rib, and at the lateral border of the erector spinae muscle it crosses the twelfth rib. The lower border of the lung is about two ribs higher than the pleural reflection.
Behind the sternum, the pleural sacs are adjacent to one another in the midline from the level of the second to fourth costal cartilages, but then diverge owing to the mass of the heart on the left.
- 1
Acromioclavicular joint
- 2
Aortic valve
- 3
Apex of heart
- 4
Areola of breast
- 5
Areolar glands of breast
- 6
Axillary tail of breast (of Spence)
- 7
Costal margin (at eighth costal cartilage)
- 8
Fourth costal cartilage
- 9
Jugular notch
- 10
Manubriosternal joint
- 11
Midpoint of clavicle
- 12
Mitral valve
- 13
Nipple of breast
- 14
Pulmonary valve
- 15
Second costal cartilage
- 16
Sixth costal cartilage
- 17
Sternoclavicular joint
- 18
Sternocleidomastoid
- 19
Third costal cartilage
- 20
Tricuspid valve
- 21
Xiphisternal joint
D
Breast
lymph drainage
There is a diffuse network of anastomosing lymphatic channels within the breast, including the overlying skin, and lymph in any part may travel to any other part . Larger channels drain most of the lymph to axillary nodes, but some from the medial part pass through the thoracic wall near the sternum to parasternal nodes adjacent to the internal thoracic vessels. These are the commonest and initial sites for cancerous spread, but other nodes may be involved (especially in the later spread of disease); these include infraclavicular and supraclavicular (deep cervical) nodes, nodes in the mediastinum, and nodes in the abdomen (via the diaphragm and rectus sheath). Spread to the opposite breast may also occur.
A
Right side of the thorax
from behind with the arm abducted and rotated
With the arm fully abducted and rotated, the medial (vertebral) border of the scapula (5) comes to lie at an angle of about 60° to the vertical, and indicates approximately the line of the oblique fissure of the lung (interrupted line). Red line indicates muscle fiber orientation of trapezius, deltoid and latissimus dorsi muscles.
- 1
Deltoid
- 2
Fifth intercostal space
- 3
Inferior angle of scapula
- 4
Latissimus dorsi
- 5
Medial border of scapula
- 6
Spine of scapula
- 7
Spinous process of third thoracic vertebra
- 8
Teres major
- 9
Trapezius
The line of the oblique fissure of the lung runs from the level of the spine of the third thoracic vertebra (7) to the sixth costal cartilage at the lateral border of the sternum (see B). With the arm fully abducted and rotated, the vertebral border of the scapula (5) is a good guide to the direction of this fissure.
B
Right side of the thorax
surface markings, from the right, with the arm abducted and rotated
The purple line indicates the extent of the pleura, and the solid orange line the lower limit of the lung; note the gap between the two at the lower part of the thorax, indicating the costodiaphragmatic recess of pleura, the lung expands into this space during inspiration. The transverse and oblique fissures of the lung are represented by the interrupted orange lines.
- 1
Costal margin
- 2
Digitations of serratus anterior
- 3
External oblique
- 4
Floor of axilla
- 5
Latissimus dorsi
- 6
Pectoralis major
The transverse fissure of the right lung is represented by a line drawn horizontally backwards from the fourth costal cartilage until it meets the line of the oblique fissure (described in A) running forwards to the sixth costal cartilage. The triangle so outlined indicates the middle lobe of the lung, with the superior lobe above it and the inferior lobe below and behind it. It is the area covered by the right breast.
On the left side, where the lung has only two lobes, superior and inferior, there is no transverse fissure; the surface marking for the oblique fissure is similar to that on the right.
* The asterisks represent the places where the lower edges of the lung and pleura cross the eighth and tenth ribs, respectively, in the mid-axillary line.
Anterior chest wall muscles of the thorax
intercostal and from the front
- 1
External intercostal muscle
- 2
External intercostal membrane
- 3
Internal intercostal muscle
- 4
Pectoralis minor muscle
- 5
Second costal cartilage
- 6
Second rib
- 7
Sixth costal cartilage
- 8
Sternal angle (Louis)
- 9
Xiphoid process
The fibres of the external intercostal muscles (1) run downwards and medially, and near the costochondral junctions (as between 5 and 6) give place to the anterior intercostal membrane (here removed); these are thin sheets of connective tissue through which the underlying internal intercostal muscles (3) can be seen.
The fibres of the internal intercostal muscles (3) run downwards and laterally. At the front, they are covered by the anterior intercostal membranes, and at the back of the thorax they give place to the posterior intercostal membranes. The different directions of the muscle fibres enable the two muscle groups to be distinguished – down and medially for the externals (1), down and laterally for the internals (3).
The seventh costal cartilage is the lowest to join the sternum and together with the eighth, ninth and tenth cartilages forms the costal margin.
Muscles of the thorax
- 1
Eighth rib
- 2
External intercostal
- 3
Fifth intercostal nerve
- 4
Fifth posterior intercostal artery
- 5
Fifth posterior intercostal vein
- 6
Fifth rib
- 7
Fourth rib
- 8
Innermost intercostal
- 9
Internal intercostal
- 10
Pleura
- 11
Seventh rib
- 12
Sixth intercostal nerve
- 13
Sixth rib
The internal intercostal muscles are continuous posteriorly with the posterior intercostal membranes which are covered by the medial ends of the external intercostals (as at 2).
Muscles of the thorax
This view of the internal surface of the thoracic wall shows the posterior surface of the right half of the sternum and adjacent wall, with the pleura removed. The internal thoracic artery (5) is seen passing deep to the slips of transversus thoracis (9, previously called sternocostalis).
- 1
Anterior intercostal vein
- 2
Body of sternum
- 3
Innermost intercostal membrane
- 4
Internal intercostal muscle
- 5
Internal thoracic artery
- 6
Internal thoracic veins
- 7
Second rib
- 8
Sixth rib
- 9
Slips of transversus thoracis muscle
- 10
Sternal angle (Louis)
- 11
Xiphoid process
- 1
Descending thoracic aorta
- 2
Eighth intercostal neurovascular bundle
- 3
Eighth rib
- 4
Innermost intercostal muscle
- 5
Twelfth rib
Root of neck and thoracic viscera
- 1
Arch of cricoid cartilage
- 2
Brachiocephalic trunk
- 3
Fibrous pericardium
- 4
First rib (cut edge)
- 5
Inferior thyroid veins
- 6
Isthmus of thyroid gland
- 7
Lateral lobe of thyroid gland
- 8
Latissimus dorsi muscle
- 9
Left axillary artery
- 10
Left axillary vein
- 11
Left brachiocephalic vein
- 12
Left common carotid artery
- 13
Left external jugular vein
- 14
Left internal jugular vein
- 15
Left lung
- 16
Left phrenic nerve
- 17
Left recurrent laryngeal nerve
- 18
Left subclavian vein
- 19
Left vagus nerve (CN X)
- 20
Pectoral branch of thoracoacromial artery
- 21
Pectoralis major
- 22
Pectoralis minor
- 23
Pulmonary artery (right)
- 24
Pulmonary vein
- 25
Right axillary vein
- 26
Right brachiocephalic vein
- 27
Right common carotid artery
- 28
Right external jugular vein
- 29
Right internal jugular vein
- 30
Right lung
- 31
Right phrenic nerve
- 32
Right recurrent laryngeal nerve
- 33
Right subclavian vein
- 34
Right vagus nerve (CN X)
- 35
Strap muscles (Infrahyoid) (reflected)
- 36
Superior vena cava
- 37
Trachea
- 38
Upper trunk of right brachial plexus
Thoracic viscera with heart in situ
- 1
Anterior interventricular artery (LAD)
- 2
Ascending aorta
- 3
Axillary vein
- 4
Brachiocephalic trunk
- 5
Coronary/atrioventricular sulcus
- 6
Costodiaphragmatic recess
- 7
Costomediastinal recess
- 8
Epicardium (visceral pericardial layer)
- 9
Fibrous pericardium
- 10
First rib (cut edge)
- 11
Inferior thyroid vein
- 12
Latissimus dorsi muscle
- 13
Left brachiocephalic vein
- 14
Left common carotid artery
- 15
Left lung
- 16
Left phrenic nerve
- 17
Left axillary artery
- 18
Left vagus nerve (CN X)
- 19
Left ventricle
- 20
Pectoral branch of thoracoacromial artery
- 21
Pectoralis minor muscle (reflected)
- 22
Rectus abdominis muscle
- 23
Right auricle (appendage)
- 24
Right brachiocephalic vein
- 25
Right common carotid artery
- 26
Right external jugular vein
- 27
Right hemidiaphragm
- 28
Right internal jugular vein
- 29
Right lung
- 30
Right phrenic nerve
- 31
Right subclavian vein
- 32
Right vagus nerve (CN X)
- 33
Serous pericardium (parietal layer)
- 34
Superior vena cava
- 35
Thoracodorsal artery
- 36
Thoracodorsal vein
- 37
Trachea
- 38
Upper trunk of left brachial plexus
Thoracic viscera with heart removed
- 1
Anterior scalene muscle and tendon
- 2
Arch of aorta
- 3
Arch of cricoid cartilage
- 4
Ascending aorta
- 5
Axillary artery (2 nd part)
- 6
Brachiocephalic trunk
- 7
Costodiaphragmatic recess
- 8
Costomediastinal recess
- 9
Fibrous pericardium
- 10
First rib (cut edge)
- 11
Inferior thyroid artery
- 12
Inferior thyroid veins
- 13
Inferior vena cava
- 14
Internal thoracic artery
- 15
Isthmus of thyroid gland
- 16
Lateral lobe of thyroid gland
- 17
Left common carotid artery
- 18
Left hemidiaphragm
- 19
Left inferior pulmonary vein
- 20
Left lung
- 21
Lingula
- 22
Pectoral branch of thoracoacromial artery
- 23
Pectoralis major (reflected)
- 24
Pectoralis minor (reflected)
- 25
Pulmonary trunk
- 26
Right bronchial artery
- 27
Right common carotid artery
- 28
Right hemidiaphragm
- 29
Right inferior pulmonary vein
- 30
Right lung
- 31
Right phrenic nerve
- 32
Right subclavian artery
- 33
Right superior pulmonary vein
- 34
Right vagus nerve (CN X)
- 35
Serous pericardium (parietal layer)
- 36
Strap muscles (Infrahyoid) (reflected)
- 37
Superior vena cava
- 38
Suprascapular artery
- 39
Thyrocervical trunk
- 40
Transverse cervical artery
- 41
Upper trunk of brachial plexus
Superoinferior view of thoracic cavity from head to diaphragm with pericardium and lungs removed
- 1
Anterior scalene muscle
- 2
Arch of cricoid cartilage
- 3
Ascending aorta
- 4
Axillary artery (second part)
- 5
Brachiocephalic trunk
- 6
Carina (internally)
- 7
Costodiaphragmatic recess
- 8
Costomediastinal recess
- 9
Cut edge 1st rib
- 10
Fibrous pericardium
- 11
Inferior lobar bronchus (left)
- 12
Inferior lobar bronchus (right)
- 13
Inferior thyroid veins
- 14
Inferior vena cava
- 15
Internal thoracic artery (reflected laterally)
- 16
Isthmus of thyroid gland
- 17
Lateral lobe of thyroid gland
- 18
Left common carotid
- 19
Left hemidiaphragm
- 20
Left inferior pulmonary vein
- 21
Left lung
- 22
Left phrenic nerve
- 23
Left pulmonary artery
- 24
Left superior pulmonary vein
- 25
Left vagus nerve
- 26
Ligamentum arteriosum
- 27
Linea alba
- 28
Middle lobar bronchus
- 29
Oesophageal plexus
- 30
Oesophagus
- 31
Parietal pleura
- 32
Pectoralis minor muscle (reflected)
- 33
Pulmonary trunk
- 34
Rectus abdominis
- 35
Right bronchial artery (arises from internal thoracic artery, variation)
- 36
Right common carotid
- 37
Right hemidiaphragm
- 38
Right inferior pulmonary vein
- 39
Right lung
- 40
Right main bronchus
- 41
Right phrenic nerve
- 42
Right pulmonary artery
- 43
Right subclavian artery
- 44
Right superior epartial bronchus
- 45
Right vagus nerve
- 46
Serous pericardium (parietal layer)
- 47
Sternum
- 48
Strap muscles (reflected)
- 49
Superior lobar bronchus
- 50
Superior right pulmonary vein
- 51
Suprascapular artery
- 52
Thoracic cardiac nerves
- 53
Thyrocervical trunk
- 54
Trachea
- 55
Transverse cervical artery
- 56
Upper trunk of left brachial plexus
- 57
Upper trunk of right brachial plexus
Superior and posterior mediastinum and cardiac plexus view from left
- 1
Anterior scalene muscle and tendon
- 2
Aortic arch
- 3
Ascending aorta
- 4
Axillary artery
- 5
Brachiocephalic trunk
- 6
Cardiac plexus (superficial)
- 7
Descending aorta
- 8
Inferior lobar bronchus
- 9
Inferior thyroid artery
- 10
Inferior thyroid vein
- 11
Inferior vena cava
- 12
Innermost intercostal muscle
- 13
Intercostal nerve
- 14
Internal thoracic artery
- 15
Isthmus of thyroid gland
- 16
Lateral lobe of thyroid gland
- 17
Left common carotid artery
- 18
Left hemidiaphragm
- 19
Left phrenic nerve
- 20
Left pulmonary artery
- 21
Left recurrent laryngeal nerve
- 22
Left subclavian artery
- 23
Left vagus nerve (CN X)
- 24
Ligamentum arteriosum
- 25
Oesophageal plexus
- 26
Oesophagus
- 27
Parietal pleura
- 28
Posterior intercostal artery
- 29
Posterior intercostal vein
- 30
Pulmonary trunk
- 31
Right common carotid artery
- 32
Right phrenic nerve
- 33
Right pulmonary artery
- 34
Right subclavian artery
- 35
Serous pericardium (parietal layer)
- 36
Superior lobar bronchus
- 37
Suprascapular artery
- 38
Sympathetic trunk (cervical)
- 39
Sympathetic trunk (thoracic)
- 40
Thoracic cardiac nerves (sympathetic)
- 41
Transverse cervical artery
- 42
Upper trunk of brachial plexus
Superior and posterior mediastinum view from the right
- 1
Anterior scalene muscle
- 2
Ascending aorta
- 3
Ascending cervical artery
- 4
Axillary artery
- 5
Brachiocephalic trunk
- 6
Cardiac plexus
- 7
Carina (internal feature)
- 8
Inferior belly of omohyoid muscle
- 9
Inferior lobar bronchus
- 10
Inferior thyroid artery
- 11
Innermost intercostal muscle
- 12
Internal thoracic artery
- 13
Isthmus of thyroid gland
- 14
Left main bronchus
- 15
Left phrenic nerve
- 16
Middle lobar bronchus
- 17
Oesophageal plexus
- 18
Oesophagus
- 19
Parietal pleura
- 20
Posterior intercostal artery
- 21
Posterior intercostal nerve
- 22
Posterior intercostal vein
- 23
Pulmonary trunk
- 24
Right bronchial artery
- 25
Right common carotid artery
- 26
Right lobe of thyroid gland
- 27
Right main bronchus
- 28
Right phrenic nerve
- 29
Right pulmonary artery
- 30
Right recurrent laryngeal nerve
- 31
Right sternocleidomastoid muscle (reflected)
- 32
Right subclavian artery
- 33
Right superior epartial bronchus
- 34
Right vagus nerve (CN X)
- 35
Strap muscles (reflected)
- 36
Superior lobar bronchus
- 37
Suprascapular artery
- 38
Sympathetic trunk
- 39
Sympathetic trunk ganglion
- 40
Thoracic cardiac nerves
- 41
Thyrocervical trunk
- 42
Trachea
- 43
Transverse cervical artery
Heart and pericardium
- A
from the front
- B
with marker in the transverse sinus
- C
oblique sinus after removal of the heart
- 1
Anterior cardiac vein
- 2
Anterior interventricular branch of left coronary artery
- 3
Ascending aorta
- 4
Auricle of left atrium
- 5
Auricle of right atrium
- 6
Diaphragm
- 7
Great cardiac vein
- 8
Inferior vena cava
- 9
Left inferior pulmonary vein
- 10
Left superior pulmonary vein
- 11
Left ventricle
- 12
Marginal branch of right coronary artery
- 13
Marker (B) black line (C) in transverse sinus
- 14
Pericardium fused with central tendon of diaphragm
- 15
Pericardium turned laterally over lung
- 16
Posterior wall of pericardial cavity and oblique sinus
- 17
Pulmonary trunk
- 18
Right atrium
- 19
Right coronary artery
- 20
Right inferior pulmonary vein
- 21
Right superior pulmonary vein
- 22
Right ventricle
- 23
Serous pericardium overlying fibrous pericardium (turned laterally)
- 24
Small cardiac vein
- 25
Superior vena cava
The right border of the heart is formed by the right atrium (A18).
The left border is formed mostly by the left ventricle (A11) with at the top the uppermost part (infundibulum) of the right ventricle (A22) and the tip of the left auricle (A4).
The inferior border is formed by the right ventricle (A22) with a small part of the left ventricle (A11) at the apex.