Surface Anatomy and Levels

Surface Anatomy

Head and Neck

  • nasion (junction frontal and nasal bones)
  • glabella
  • superciliary arch (above supraorbital margin)
  • temporal line (curves up and back)
  • parietal eminence (above posterior temporal line)
  • greatest transverse diameter (betw parietal eminences)
  • median nuchal furrow (below ext occipital protuberence, overlying ligamentum nuchae)
  • inion (tip ext occipital protuberence)
  • maximum occipital point (greatest convex curvature above ext occasionally protuberence)
  • lambda (above max occasionally point)
  • superior nuchal line (lat from ext occasionally prot)
  • anterior triangle (betw midline, SCM, mandible))
  • posterior triangle (betw SCM, trapezius, clavicle)

Abdomen

  • xiphisternal plane (horizontal)
  • transpyloric plane (halfway between suprasternal notch and symphysis pubis)
  • subcostal plane (10th costal cartilages)
  • supracristal plane (highest iliac crest)
  • mid-clavicular/lateral/mammary lines (>mid between ASIS and symphysis pubis)
  • abdominal regions (xiphoid and symphysis pubis in 1/3s, mid-clavicular lines) = epigastrium, R&L hypochondrium/ subcostal, umbilical/periumbilical, R&L lumbar, hypogastrium/suprapubic, R&L iliac region/fossa

Back

  • median furrow (external occipital protuberance > natal cleft)
  • sacral dimple (PSIS)

Limbs

  • infraclavicular fossa = deltopectoral triangle (betw pectoralis major and deltoid; cephalic v)
  • anatomical snuffbox = radial fossa (extensor pollicus longus, extensor pollicus brevis/abductor pollicus longus, styloid process radius, trapezium/scaphoid; radial a, cephalic v, dorsal cutaneous br of radial n)
  • proximal transverse wrist skin crease (ant line of the wrist joint)
  • distal trans wrist skin crease (proximal carpal bones)
  • lateral longitudinal arch of the foot
  • medial longitudinal arch = instep

Vertebral Levels

  • C1/2 – open mouth
  • C3 – hyoid
  • C4 – superior thyroid notch, bifurcation CCA
  • C6 – cricoid cartilage, junction pharynx/oesophagus
  • T2/3 – suprasternal notch
  • T3 – superior mediastinum, spine of scapula, formation SVC
    • midline: manubrium, brachiocephalic vv > SVC (L crossing anterior to aa), brachiocephalic a (R of trachea), LCCA and L SCA (L of trachea), trachea, oesophagus, vertebra, erector spinae
    • paramedian: ribs, upper lobes, trapezius
    • lat: pectoralis major and minor, axillary fat, deltoid, subscapularis, scapula, infraspinaous, spine of scapula, supraspinatus
  • T4 – sternal angle, 2nd costal cartilage, junction sup/inf mediastinum, aortic arch, azygos vein>SVC
    • midline: sternal angle, anterior junction line, SVC(R) with azygos arch, trachea, oesophagus, aortic arch (L), lower border T4, erector spinae
    • paramedian: upper lobes, oblique fissure, lower lobe
  • T5 – carina, birfurcation of PT
    • midline: body sternum, anterior junction line, ascending aorta, bifurcation of pulmonary trunk, SVC, superior pulmonary vv, carina/main bronchi, oesophagus, azygos v, azygo-oesophageal rescess, descending aorta, vertebra, erector spinae
  • T6 – upper heart
    • midline: RA appendage (R), RVOT (L), RCA, aortic root, LCA, SVC, LA appendage, pulmonary vv, oesophagus, azygos v, azygo-oesophageal recess, descending aorta
  • T7 – apex scapula
  • T8/9 – xiphisternal joint, xiphisternal plane
    • upper liver, central diaphragm, lower heart, fundus stomach
  • T10 – hepatic vv, OGJ
    • diaphgram, liver (with hepatic vv>IVC), stomach and OGJ, spleen, descending aorta, azygos and hemiazygos vv
  • T11 – upper liver and spleen
    • liver (II, fissure for ligamentum venosum, IVa VIII, VII), IVC, R adrenal, UP RK, stomach, spleen, lower L lung
    • midline: crura, retrocrural space (aorta, azygos, hemiazygos, thoracic duct), vertebra, erector spinae
    • chest wall: recti (w liniea alba), serratus ant, costal cartilages, ribs, intercostal mm, latissimus dorsi
  • T12 – porta, coeliac axis, splenic hilum
    • liver (R&L hep a, BD, portal vv), IVC UP R&L kidney, L adrenal, coeliac axis, aorta (inferior phrenic aa, celiac axis), stomach, splenic flexure, spleen)
  • L1 – transpyloric plane
    • R±L lobe liver, GB fundus, D1, pylorus, stomach, pancreas (body and tail), confluence of portal v, aorta (SMA, renal aa), IVC and renal vv, renal hila, splenic flexure, spleen, spinal conus
  • L2 – pancreatic head
    • proper abdo wall, lower R liver, GB neck, GDA, head pancreas, SMA&V, uncinate process, D2, ampulla of Vater, D4, jejunum, transverse colon, crura, aorta, IVC, LP kidneys, psoas
  • L3 – inferior costal margin, subcostal plane
    • transverse, ascending and descending colon, jejunum, SMA&V, D3, IVC, R crus, aorta (IMA), psoas
  • L3/4 – umbilicus
  • L4 – supracristal plane, aortic bifurcation
  • L5 – confluence of IVC
  • S2 – sacral dimples, centre SIJs, termination dural sac
  • midsacral level:
    • midline: rectus, ileum, caecum, bladder, ureters, sigmoid-rectal junction, sacrum, posterior neural foramina
    • lateral: inferior epigastric vessels, iliacus, external iliac a&v, psoas, ischium, gluteus minimus, medius, internal iliac a&v, sciatic nerve, piriformis, gluteus maximus
  • lower sacral level:
    • midline: recti, bladder, VUJ or seminal vesicles, uterus, ovaries, pararectal fat, perirectal fascia, rectum, coccyx
    • lateral: sartorius, inguinal ligament, iliopsoas, femoral sheath (n&a&v), acetabulum, femoral head, obturator internus, internal iliac a&v, gluteus medius, minimus, maximus
  • perineum:
    • midline: symphysis pubis, urogenital triangle (prostate gland, urethra, vagina), anal triangle (anorectal junction, ishiorectal fossa), puborectalis and external anal sphincter, coccyx
    • lateral: obturator internus, ischial tuberosity, sacrotuberous ligament, gluteus maximus